Bicycle gearbox having segmented sprockets

ABSTRACT

A gearbox may include a drive spindle and several interconnected gear clusters arranged in a housing. A first of the gear clusters is coaxially fastened to the spindle, and has an outboard gear and an inboard gear. The first gear cluster drives a belt or chain to operate one or more of the other gear clusters, and the inboard gear is physically divided into a plurality of segments. A shifting system for the gearbox includes an actuator configured to urge the segments of the inboard gear of the first gear cluster into and out of the plane of the belt or chain via a toggle and slider mechanism, such that a gear ratio of the gearbox is changeable without displacing the belt or chain out of the plane.

CROSS-REFERENCES

The following applications and materials are incorporated herein, intheir entireties, for all purposes: U.S. patent application Ser. No.17/152,483, filed Jan. 19, 2021; U.S. patent application Ser. No.16/792,050, filed Feb. 14, 2020; U.S. patent application Ser. No.16/998,010, filed Aug. 20, 2020; U.S. Provisional Patent ApplicationSer. No. 62/963,064, filed Jan. 19, 2020; and U.S. Provisional PatentApplication Ser. No. 63/067,911, filed Aug. 20, 2020.

FIELD

This disclosure relates to systems and methods for shifting gears on abicycle or other geared vehicle. More specifically, this disclosurerelates to gearboxes.

INTRODUCTION

A bicycle drivetrain transmits power from a rider of a bicycle to thebicycle's wheels. The drivetrain typically includes two pedals attachedto respective crankarms on opposing sides of the bicycle frame. Thepedals are rotationally coupled to a gearing system, which typically hasa plurality of different gear ratios and a mechanism for shifting gearsto effect a desired gear ratio. On a bicycle having a gearbox, thegearing system is at least partially enclosed in a gearbox disposed onand/or incorporated into the bicycle frame. An advantage of the gearboxis that the gearing system within the box may be protected from exposureto dirt and moisture, as well as from damaging impacts. Anotheradvantage is that the gearbox is suitable for mounting on the bicycleframe adjacent the crankarms, where the weight of the gearbox has alower impact on bicycle handling than it typically would if the gearboxwere mounted elsewhere (e.g., further from the bicycle center ofgravity). Accordingly, further advancements in bicycle gearboxtechnology are desirable.

SUMMARY

The present disclosure provides systems, apparatuses, and methodsrelating to bicycle gearboxes having segmented sprockets.

In some examples, a method for shifting a segmented gear includes:rotating a gear cluster comprising a first gear and a coaxial secondgear, wherein the gear cluster is operatively coupled to a powertransfer mechanism, wherein a power transfer mechanism defines a planeand is wrapped partially around the first gear, and wherein the firstgear has a plurality of gear segments independently movable into and outof the plane; rotating a plurality of radially transitionable sliders intandem with the first gear, each of the sliders having one or moreprotrusions and coupled to a corresponding one of the gear segments ofthe first gear; pivoting a toggle into a first position such that afirst ramped face of the toggle is in a path of the one or moreprotrusions of the sliders; and sequentially moving each segment of thefirst gear out of the plane of the power transfer mechanism by urgingthe slider radially when the one or more protrusions strike the firstramped face of the toggle, such that the power transfer mechanism wrapsat least partially around the second gear.

In some examples, a method for shifting a segmented gear includes:rotating a gear cluster comprising a first gear and a coaxial secondgear using a power transfer mechanism, wherein the power transfermechanism defines a plane and is wrapped partially around the firstgear, and wherein the first gear has a plurality of gear segmentsindependently pivotable into and out of the plane; rotating a pluralityof radially transitionable sliders in tandem with the first gear, eachof the sliders having one or more protrusions and coupled to acorresponding one of the gear segments of the first gear; pivoting atoggle into a first position using a linear actuator, such that a firstcontoured face of the toggle is in a first path of the one or moreprotrusions of the sliders; and sequentially moving each segment of thefirst gear out of the plane of the power transfer mechanism by urgingthe slider radially when the one or more protrusions strike the firstcontoured face of the toggle, such that the power transfer mechanismwraps at least partially around the second gear.

Features, functions, and advantages may be achieved independently invarious embodiments of the present disclosure, or may be combined in yetother embodiments, further details of which can be seen with referenceto the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an illustrative gearbox in accordance withaspects of the present disclosure.

FIG. 2 is an isometric view of a gearbox which is an example of thegearbox depicted in FIG. 1 .

FIG. 3 is an isometric view of the gearbox of FIG. 2 with portions ofthe housing removed.

FIG. 4 is a top-down view of the gearbox of FIG. 2 with the housingremoved.

FIG. 5 is an illustrative gear segment in a pivoted position and shiftwedge in a first position in accordance with aspects of the presentdisclosure.

FIG. 6 is an illustrative gear segment in a pivoted position and shiftwedge in a second position in accordance with aspects of the presentdisclosure.

FIG. 7 is an illustrative gear segment in a planar position and shiftwedge in a second position in accordance with aspects of the presentdisclosure.

FIG. 8 is an illustrative gear segment in a planar position and shiftwedge in a first position in accordance with aspects of the presentdisclosure.

FIG. 9 is a sectional view of the gearbox of FIG. 2 taken along a lineindicated in FIG. 4 .

FIG. 10 is a sectional view of the gearbox of FIG. 2 taken along a lineindicated in FIG. 4 .

FIG. 11 is an exploded view of the gearbox of FIG. 2 .

FIG. 12 is a section view of the gearbox of FIG. 2 taken along a lineindicated in FIG. 3 .

FIG. 13 is an isometric view of a layshaft in accordance with aspects ofthe present disclosure.

FIG. 14 is an isometric view of the layshaft of FIG. 13 having gearclusters attached thereon.

FIG. 15 is an exploded view of a portion of the gearbox of FIG. 2 .

FIG. 16 is a partial exploded view of the portion of FIG. 15 .

FIG. 17 is a front view of a first gear cluster in accordance withaspects of the present disclosure.

FIG. 18 is a rear view of the gear cluster of FIG. 17 .

FIG. 19 is an isometric view of the gear cluster of FIG. 17 .

FIG. 20 is a front view of a second gear cluster in accordance withaspects of the present disclosure.

FIG. 21 is a rear view of the gear cluster of FIG. 20 .

FIG. 22 is an isometric view of the gear cluster of FIG. 20 .

FIG. 23 is a front view of a third gear cluster in accordance withaspects of the present disclosure.

FIG. 24 is a rear view of the gear cluster of FIG. 23 .

FIG. 25 is an isometric view of the gear cluster of FIG. 23 .

FIG. 26 is a front view of a fourth gear cluster in accordance withaspects of the present disclosure.

FIG. 27 is a rear view of the gear cluster of FIG. 26 .

FIG. 28 is an isometric view of the gear cluster of FIG. 26 .

FIG. 29 is a portion of an illustrative shifting system engaged withgear clusters in accordance with aspects of the present disclosure.

FIG. 30 is a sectional view of a belt-driven gearing system inaccordance with aspects of the present disclosure.

FIG. 31 is a sectional view of the belt-driven gearing system of FIG. 30.

FIG. 32 is a front view of a first belt-driven gear cluster of thegearing system of FIG. 30 .

FIG. 33 is a rear view of the gear cluster of FIG. 32 .

FIG. 34 is an isometric view of the gear cluster of FIG. 32 .

FIG. 35 is a front view of a second belt-driven gear cluster of thegearing system of FIG. 30 .

FIG. 36 is a rear view of the gear cluster of FIG. 35 .

FIG. 37 is an isometric view of the gear cluster of FIG. 35 .

FIG. 38 is a front view of a third belt-driven gear cluster of thegearing system of FIG. 30 .

FIG. 39 is a rear view of the gear cluster of FIG. 38 .

FIG. 40 is an isometric view of the gear cluster of FIG. 38 .

FIG. 41 is a front view of a fourth belt-driven gear cluster of thegearing system of FIG. 30 .

FIG. 42 is a rear view of the gear cluster of FIG. 41 .

FIG. 43 is an isometric view of the gear cluster of FIG. 41 .

FIG. 44 is an isometric view of a gearbox which is an example of thegearbox depicted in FIG. 1 .

FIG. 45 is an isometric view of the gearbox of FIG. 44 with the crankarmremoved.

FIG. 46 is a top-down view of the gearbox of FIG. 44 with the housingremoved.

FIG. 47 is a sectional view of the gearbox of FIG. 44 taken along a lineindicated in FIG. 46 .

FIG. 48 is a sectional view of the gearbox of FIG. 44 taken along a lineindicated in FIG. 46 .

FIG. 49 is a sectional view of the gearbox of FIG. 44 taken along a lineindicated in FIG. 45 .

FIG. 50 is a sectional view of the gearbox of FIG. 44 taken along a lineindicated in FIG. 45 .

FIG. 51 is a profile view of an illustrative shifting system for usewith the gearbox of FIG. 44 .

FIG. 52 is a profile view of the shifting system of FIG. 51 with themounting plate removed.

FIG. 53 is a profile view of the shifting system of FIG. 51 for use witha single gear cluster.

FIG. 54 is an isometric view of the shifting system of FIG. 53 furtherdepicting an illustrative gear cluster.

FIG. 55 is a front view of the shifting system of FIG. 53 furtherdepicting a gear cluster.

FIG. 56 is a front view of an illustrative shifting slider and toggle ofthe shifting system of FIG. 9 .

FIG. 57 is an isometric view of the shifting slider and toggle of FIG.56 .

FIG. 58 is a front view of an illustrative first gear cluster inaccordance with aspects of the present disclosure.

FIG. 59 is a rear view of the gear cluster of FIG. 58 .

FIG. 60 is an isometric view of the gear cluster of FIG. 58 .

FIG. 61 is a front view of an illustrative second gear cluster inaccordance with aspects of the present disclosure.

FIG. 62 is a rear view of the gear cluster of FIG. 61 .

FIG. 63 is an isometric view of the gear cluster of FIG. 61 .

FIG. 64 is a front view of an illustrative third gear cluster inaccordance with aspects of the present disclosure.

FIG. 65 is a rear view of the gear cluster of FIG. 64 .

FIG. 66 is an isometric view of the gear cluster of FIG. 64 .

FIG. 67 is a front view of an illustrative fourth gear cluster inaccordance with aspects of the present disclosure.

FIG. 68 is a rear view of the gear cluster of FIG. 67 .

FIG. 69 is an isometric view of the gear cluster of FIG. 67 .

FIG. 70 depicts an illustrative shifting system for use with gearboxesof the present disclosure.

FIG. 71 depicts the shifting system of FIG. 70 for use with a singlegear cluster in a first position.

FIG. 72 depicts the shifting system of FIG. 70 for use with a singlegear cluster in a second position.

FIG. 73 is another view of the shifting system of FIG. 70 in the firstposition, corresponding to FIG. 71 .

FIG. 74 is another view of the shifting system of FIG. 70 in the secondposition, corresponding to FIG. 72 .

FIG. 75 is a profile view of an illustrative chain tensioner for usewith gearboxes of the present disclosure.

DETAILED DESCRIPTION

Various aspects and examples of a gearbox having segmented sprocketclusters and a corresponding shifting system, as well as relatedmethods, are described below and illustrated in the associated drawings.Unless otherwise specified, a gearbox in accordance with the presentteachings, and/or its various components, may contain at least one ofthe structures, components, functionalities, and/or variationsdescribed, illustrated, and/or incorporated herein. Furthermore, unlessspecifically excluded, the process steps, structures, components,functionalities, and/or variations described, illustrated, and/orincorporated herein in connection with the present teachings may beincluded in other similar devices and methods, including beinginterchangeable between disclosed embodiments. The following descriptionof various examples is merely illustrative in nature and is in no wayintended to limit the disclosure, its application, or uses.Additionally, the advantages provided by the examples and embodimentsdescribed below are illustrative in nature and not all examples andembodiments provide the same advantages or the same degree ofadvantages.

This Detailed Description includes the following sections, which followimmediately below: (1) Definitions; (2) Overview; (3) Examples,Components, and Alternatives; (4) Advantages, Features, and Benefits;and (5) Conclusion. The Examples, Components, and Alternatives sectionis further divided into subsections, each of which is labeledaccordingly.

Definitions

“Comprising,” “including,” and “having” (and conjugations thereof) areused interchangeably to mean including but not necessarily limited to,and are open-ended terms not intended to exclude additional, unrecitedelements or method steps.

Terms such as “first”, “second”, and “third” are used to distinguish oridentify various members of a group, or the like, and are not intendedto show serial or numerical limitation.

“AKA” means “also known as,” and may be used to indicate an alternativeor corresponding term for a given element or elements.

“Elongate” or “elongated” refers to an object or aperture that has alength greater than its own width, although the width need not beuniform. For example, an elongate slot may be elliptical orstadium-shaped, and an elongate candlestick may have a height greaterthan its tapering diameter. As a negative example, a circular aperturewould not be considered an elongate aperture.

The terms “inboard,” “outboard,” “forward,” and “aft” (and the like) areintended to be understood in the context of a host vehicle, such as abicycle, on which systems described herein may be mounted or otherwiseattached. For example, “outboard” may indicate a relative position thatis laterally farther from the centerline of the vehicle, or a directionthat is away from the vehicle centerline. Conversely, “inboard” mayindicate a direction toward the centerline, or a relative position thatis closer to the centerline. Similarly, “forward” means toward the frontportion of the vehicle, and “aft” means toward the rear of the vehicle.In the absence of a host vehicle, the same directional terms may be usedas if the vehicle were present. For example, even when viewed inisolation, a component may have a “forward” edge, based on the fact thatthe component would be installed with the edge in question facing in thedirection of the front portion of the host vehicle.

“Coupled” means connected, either permanently or releasably, whetherdirectly or indirectly through intervening components.

“Resilient” describes a material or structure configured to respond tonormal operating loads (e.g., when compressed) by deforming elasticallyand returning to an original shape or position when unloaded.

“Rigid” describes a material or structure configured to be stiff,non-deformable, or substantially lacking in flexibility under normaloperating conditions.

“Elastic” describes a material or structure configured to spontaneouslyresume its former shape after being stretched or expanded.

Directional terms such as “up,” “down,” “vertical,” “horizontal,” andthe like should be understood in the context of the particular object inquestion. For example, an object may be oriented around defined X, Y,and Z axes. In those examples, the X-Y plane will define horizontal,with up being defined as the positive Z direction and down being definedas the negative Z direction.

“Processing logic” describes any suitable device(s) or hardwareconfigured to process data by performing one or more logical and/orarithmetic operations (e.g., executing coded instructions). For example,processing logic may include one or more processors (e.g., centralprocessing units (CPUs) and/or graphics processing units (GPUs)),microprocessors, clusters of processing cores, FPGAs (field-programmablegate arrays), artificial intelligence (AI) accelerators, digital signalprocessors (DSPs), and/or any other suitable combination of logichardware.

A “controller” or “electronic controller” includes processing logicprogrammed with instructions to carry out a controlling function withrespect to a control element. For example, an electronic controller maybe configured to receive an input signal, compare the input signal to aselected control value or setpoint value, and determine an output signalto a control element (e.g., a motor or actuator) to provide correctiveaction based on the comparison. In another example, an electroniccontroller may be configured to interface between a host device (e.g., adesktop computer, a mainframe, etc.) and a peripheral device (e.g., amemory device, an input/output device, etc.) to control and/or monitorinput and output signals to and from the peripheral device.

“Providing,” in the context of a method, may include receiving,obtaining, purchasing, manufacturing, generating, processing,preprocessing, and/or the like, such that the object or materialprovided is in a state and configuration for other steps to be carriedout.

In this disclosure, one or more publications, patents, and/or patentapplications may be incorporated by reference. However, such material isonly incorporated to the extent that no conflict exists between theincorporated material and the statements and drawings set forth herein.In the event of any such conflict, including any conflict interminology, the present disclosure is controlling.

Overview

In general, a gearbox in accordance with aspects of the presentteachings includes gear clusters (AKA cogsets, cassettes, and/orsprocket clusters) coupled by one or more chains and/or belts and atleast partially contained within a housing, wherein one or more of thegear clusters has a segmented sprocket. A shifter is configured to movethe sprocket segments relative to a plane defined by a chain or beltassociated with that sprocket. The housing may be mounted on and/orintegral with a bicycle or other suitable vehicle. Each gear clusterincludes at least one sprocket, also referred to as a gear. At least oneof the gear clusters is mounted on a spindle (AKA an axle or a shaft)coupled at either end to bicycle crankarms (AKA cranks) and/or a drivemotor, and at least one other of the gear clusters is mounted on alayshaft. Chains, belts, and/or any other suitable coupling devicecouple a gear cluster on the spindle to a gear cluster on the layshaft,such that rotation of one of the gear clusters causes rotation of theother gear cluster. Each chain or belt may selectively engage individualsprockets in a cluster. The combination of sprockets coupled to eachchain or belt at a given moment determines the current gear ratio of thegearbox.

Shifting gear ratios of the gearbox may include sequential displacementof the segments of a selected segmented gear, such that the chain orbelt is shifted onto a different sprocket or gear of the gear clusterwithout displacing the chain or belt in a lateral direction.Repositioning of the gear segments is performed at a respective timewhen each segment is unloaded (i.e., free of the chain/belt), such thatshifting may be performed under load without negative consequences.Multiple segmented sprockets of the gearbox may be simultaneouslyshifted in this manner, if desired.

Examples, Components, and Alternatives

The following sections describe selected aspects of illustrative bicyclegearboxes as well as related systems and/or methods. The examples inthese sections are intended for illustration and should not beinterpreted as limiting the scope of the present disclosure. Eachsection may include one or more distinct embodiments or examples, and/orcontextual or related information, function, and/or structure.

A. Schematic Diagram of a Gearbox of the Present Disclosure

As shown schematically in FIG. 1 , this section describes anillustrative gearbox 100 having segmented gear clusters. Gearbox 100includes a housing 102 having a gearing system disposed within. Thegearing system includes a plurality of (e.g., four) gear clusters,namely a first gear cluster 108, a second gear cluster 114, a third gearcluster 118, and a fourth gear cluster 122, arranged as shown in FIG. 1. Each gear cluster has a plurality of individual gears labeled 1through N. Each gear of the cluster has a plurality of individual gearsegments labeled 1 through M. In some examples, each gear of each gearcluster has the same number of gear segments. In some examples, thenumber of segments may vary from gear to gear.

Each gear comprising gear segments is referred to as a segmented gear.Each gear segment is shaped as an annular sector. In some examples, asegmented gear comprises four gear segments. A selected gear of eachgear cluster is coupled to (i.e., engaged with) a chain by teetharranged around a periphery thereof. In some examples, two or more gearclusters may be engaged with the same chain. Each gear segment of asegmented gear is movable with respect to the chain. The movement ofgear segments is utilized to shift between gear ratios. In someexamples, each gear segment may be pivotable about a hinge jointdisposed at an axle end of the segment. In some examples, each gearsegment may be linearly displaceable (e.g., translated or shiftedaxially).

Gearbox 100 includes an associated shifting system 110. Shifting system110 is configured to individually move segments of the segmented gearsinto and out of engagement with the respective chain. Shifting system110 may be coupled to a controller 126, which is configured to sendcommand signals to one or more actuators of the shifting system tochange gear ratios. For example, controller 126 may signal the shiftingsystem to increase the gear ratio. Shifting is described further insections below.

In principle, gearbox 100 may be operable with any gear ratio achievableby the installed cogsets. In some cases, however, controller 126 isconfigured to allow a rider to select only a subset of gear ratios. Forexample, in some cases two or more different combinations of gears mayproduce identical or nearly identical gear ratios. Providing the vehicleoperator with a set of selectable gear combinations that includesdifferent gear combinations that result in substantially the same gearratio may be unhelpful and confusing. Accordingly, shifting system 110and/or controller 126 may be configured to enable selection of only oneof the redundant gear combinations.

Gearbox 100 includes a crankset 104 disposed outside of housing 102 andcoupled to a spindle 106. Spindle 106 passes through housing 102 toengage first gear cluster 108, such that rotation of the crankset causesrotation of the spindle which, in turn, causes rotation of the firstgear cluster.

First gear cluster 108 is coupled to a first chain 112 such thatrotation of the gear cluster causes rotation of the chain. First chain112 may be oriented orthogonally with respect to spindle 106.

First chain 112 is coupled to second gear cluster 114, therebytransmitting power from cluster 108 to cluster 114. Second gear cluster114 is coupled to third gear cluster 118 via a layshaft 116.Accordingly, rotation of chain 112 using the crankshaft and first gearcluster drives the rotation of second gear cluster 114, which rotateslayshaft 116 and third gear cluster 118. Layshaft is generally parallelto and spaced from spindle 106. Third gear cluster 118 is coupled to asecond chain 120 which is further coupled to a fourth gear cluster 122,such that rotation of third gear cluster 118 causes rotation of fourthgear cluster 122.

Fourth gear cluster 122 is coupled to an external chainring 124 (i.e.,disposed outside of housing 102) via an output shaft 123 that passesthrough housing 102. Output shaft 123 is coaxial with spindle 106, suchthat spindle 106 passes through the center of output shaft 123. Spindle106 and output shaft 123 are configured to rotate independently withrespect to one another. Chainring 124 is coupled to an output system 130(e.g., a rear wheel) via a third chain 128.

In some examples, more or fewer gear clusters and/or layshafts may beincluded. For example, a two-cluster version of gearbox 100 may includefirst gear cluster 108 on spindle 106, chain 112, and second gearcluster 114 on layshaft 116. In this example, gear clusters 118 and 122are excluded, and the drive output is via a chainring 124′ coupled tolayshaft 116′ as shown in dashed outline in FIG. 1 . In other examples,additional gear clusters may be interspersed with those shown in FIG. 1, to provide additional gear ratios and combinations.

B. First Illustrative Gearbox

This section describes a gearbox 200, which is an example of gearbox 100described above. See FIGS. 2-27 .

As shown in FIGS. 2 and 3 , gearbox 200 includes a housing 202. Thehousing at least partially contains a gearing system, as describedabove. An Illustrative gearing system for gearbox 200 is describedfurther below. A spindle 206 extends through the housing. A firstcrankarm 204 and a second crankarm (not shown) are coupled to respectiveends of spindle 206. A chainring 224 couples gearbox 200 to a wheel,e.g., a rear wheel, via an external drive chain or belt (not shown).

FIG. 4 is a top view of gearbox 200. Gearbox 200 includes a layshaft 216and four gear clusters: a first (input) gear cluster 208 (also referredto as cluster 1) disposed on spindle 206, a second gear cluster 214(also referred to as cluster 2) disposed on layshaft 216, a third gearcluster 218 (also referred to as cluster 3) disposed on layshaft 216,and a fourth gear cluster 222 (also referred to as cluster 4) disposedon an output shaft 223 (AKA a driven shaft), an example of output shaft123. First gear cluster 208 is coupled to second gear cluster 214 by afirst chain 212. Similarly, third gear cluster 218 is coupled to fourthgear cluster 222 by a second chain 220.

Accordingly, rotation of spindle 206 (e.g., by a bicycle rider operatingpedals attached to the crankarms and/or by a motor) transmits power fromfirst gear cluster 208 via first chain 212 to second gear cluster 214,and from the second gear cluster via the layshaft to third gear cluster218. Second chain 220 transmits power from third gear cluster 218 tofourth gear cluster 222, and power is transmitted from the fourth gearcluster via output shaft 223 to chainring 224, and/or to anothersuitable system.

Each of the gear clusters may include a plurality of gears, one or moregears of the plurality of gears having a plurality of gear segments.Gears comprising gear segments may be referred to as segmented gears.Each gear segment may be shaped as an annular sector. In one example,each segmented gear comprises four gear segments. Each gear segment isrotatably attached to a hinge disposed near the center of the segmentedgear. One or more gear clusters may have a non-segmented sprocket havinga smaller diameter than the respective segmented gear. Each gear segmentmay be attached to a pin. Each gear segment pivots (or folds) in adirection transverse to the plane of the gear. In other words, each gearsegment may transition between a coplanar position and a pivoted (AKAfolded) position. This configuration may enable a segmented gear totransition (e.g., stepwise) between a coplanar configuration (i.e., withall segments aligned to form a substantially coplanar gear) and apivoted (AKA pyramidal) configuration (i.e., with all gear segmentsrotationally skewed in the same direction away from the plane formed inthe coplanar configuration)

As shown in FIG. 4 , a shifting system 210 is disposed at leastpartially within the gearbox, in a generally central location. Shiftingsystem 210 is an example of shifting system 110 described above.

Shifting system 210 includes a shift rod 248 attached to a shift wedge250 configured to selectively and mechanically interface with portionsof the gear segments. Although shift rods are depicted and describedherein, any suitable actuator configured to rotate the shift wedges maybe utilized, such as a flexible cable or the like, whether manually orelectromechanically operated, e.g., by an electronic controller. Manualhandles at the upper ends of the shift rods, depicted in FIG. 3 andelsewhere, are shown for purposes of understanding, e.g., where acontroller would actuate the shifting system.

Shift wedge 250 includes a pair of ramps referred to herein as a rampedfirst face 252 and a ramped second face 254 (i.e., a first ramp and asecond ramp), generally configured such that planar extensions of eachface intersect at an angle (e.g., an acute angle). Rotation of shift rod248 simultaneously rotates shift wedge 250, thereby changing theorientation of shift wedge 250 (and the first and second faces/ramps).

In the current example, shifting system 210 has a shift rod and shiftwedge for each gear cluster. In some examples, two or more gear clustersmay share a shift wedge. For example, third gear cluster 218 and fourthgear cluster 222 may share the same shift wedge. FIGS. 25 and 26 depictsystem 210 shifting the gear ratio of gearbox 200 by causing thesegments of a segmented gear to pivot into or out of alignment with thechain.

FIGS. 5-8 depict a portion of the shifting system to facilitate thefollowing description thereof. Each of FIGS. 5-8 depict a single gearsegment, which is rotating in a generally horizontal plane into thepage, and a shift wedge in a series of positions configured to eithercause the gear segment to pivot in a selected direction or to avoid thegear segment, as the case may be. FIG. 5 is an isometric view of thesingle gear segment and shift wedge 250. Shift wedge 250 is in a firstposition configured such that the shift wedge does not interfere withthe pin of the gear segment. In this configuration, the gear segment isin its pivoted position. This position of the gear segment correspondsto a first gear ratio in which the present gear segment is tilted out ofthe plane of the chain (i.e., not engaged with the chain).

In FIG. 6 , shift wedge 250 is shown in a second position configuredsuch that the shift wedge is in the path of the pin of the gear segment.More specifically, in this position, second face 254 has been broughtinto the path of the pin of the gear segment. Accordingly, furtherrotation of the gear segment brings the pin into contact with secondface 254 and thereby slides along face 254 in the direction indicated bythe arrow. This pivots the gear segment into its coplanar position (seeFIG. 7 ) (i.e., in the plane of the chain) and thus the chain engagesthe segment.

FIG. 7 depicts the gear segment in its coplanar position and shift wedge250 in the second position. In this configuration, the shift wedge doesnot interfere with the pin of the gear segment. In other words, thisconfiguration corresponds to operation of the system in a second gearratio in which the present gear segment is engaged with the chain andable to freely rotate without striking the shift wedge.

In FIG. 8 , shift wedge 250 is again in the first position. Because thegear segment is coplanar with the chain, the shift wedge is now in thepath if the pin of the gear segment. More specifically, in thisposition, first face 252 has been brought into the path of the pin ofthe gear segment. Accordingly, further rotation of the gear segmentbrings the pin into contact with first face 252 and thereby slides alongface 252 in the direction indicated by the arrow. This pivots the gearsegment into its pivoted (i.e., non-coplanar) position, and the gearsegment and wedge are again as depicted in FIG. 5 .

Accordingly, shifting system 210 includes a shifting wedgetransitionable between: (a) a first configuration, in which a firstramped face of the wedge is in line with the pin of each segment of theinboard gear of the first gear cluster when the segment is out of theplane of its chain, such that rotating the pin into the first rampedface is configured to urge the segment into the plane of the chain, and(b) a second configuration, in which a second ramped face of the wedgeis in line with the pin of each segment of the inboard gear of the firstgear cluster when the segment is in the plane of its chain, such thatrotating the pins into the second ramped face is configured to urge thesegment out of the plane of the chain.

As shown in FIG. 9 , gearbox 200 includes a first chain tensioner 232.Chain tensioner 232 has at least one idler 236 having a fixed locationand at least one adjustable gear 238 configured to be moved ortranslated by a pushrod 240. In some examples, chain tensioner 232includes two idlers and one adjustable gear. A spring is coaxiallymounted to pushrod 240 to provide a biasing force. Chain tensioner 232may be configured to engage any of the chains described above. In thecurrent example, idler 236 and gear 238 of chain tensioner 232 areconfigured to engage chain 220. Accordingly, chain 220 interfaces withthird gear cluster 218, fourth gear cluster 222, and chain tensioner232.

Chain tensioner 232 is configured such that pushrod 240 can be utilizedto displace gear 238, thereby applying more or less tension to theengaged chain. Manipulation of pushrod 240 may be manual (e.g., by auser), and/or may be automatic (e.g., using mechanical and/or electriccomponents).

As shown in FIG. 10 , gearbox 200 includes a second chain tensioner 234,which is substantially similar to chain tensioner 232. In the currentexample, chain tensioner 234 includes a single idler 242 and a movablegear 244 attached to a pushrod 246. Second chain tensioner is configuredto engage first chain 212. Accordingly, chain 212 is configured tointerface with first gear cluster 208, second gear cluster 214, andchain tensioner 234. Any suitable chain tensioners may be utilized.

FIG. 11 depicts an exploded view of portions of gearbox 200. The firstgear cluster is configured to be driven by the vehicle's prime mover(e.g., human-powered pedaling and/or electric motor) via spindle 206.Each gear of first gear cluster 208 is configured to selectively engagefirst chain 212, which may include one or more chains, belts, and/or anyother suitable power transfer devices.

In the current example, first gear cluster 208 comprises two segmentedgears, 208A and 208B. Affixed to each gear segment of segmented gear208A is a pin 211. Each gear segment of segmented gear 208A shares acommon hinge portion 209 with a corresponding gear segment of segmentedgear 208B, in a fixed angular relationship. Hinge portion 209 isconfigured to mate with a hinge receiver 256 disposed on spindle 206.Hinge receiver 256 may be unitary with spindle 206 or may be affixed bya suitable mechanism (e.g., screws, friction fit, etc.). Correspondingsegments of the two gears are configured to pivot together, rather thanindependently (see FIGS. 17-19 ). In other words, when a segment of gear208A is shifted out of the plane of chain 212, the corresponding segmentof 208B is brought into the plane of chain 212 (thereby engaging thechain).

First gear cluster 208 is coupled to second gear cluster 214 by firstchain 212. The system is configured such that first chain 212 directlyengages a single one of the gears of first gear cluster 208 and a singleone of the gears of second gear cluster 214 at any given time; however,the chain may partially engage more than one of the gears of eachcluster at some stages of operation, such as when the chain is beingsegmentally shifted from one gear to another (e.g., in response to userand/or controller input).

Second gear cluster 214 is securely mounted on layshaft 216 such thatrotation of second gear cluster 214 also rotates the layshaft. Secondgear cluster 214 has a nested arrangement, such that a segmented gear214A and a non-segmented sprocket 214B are nestable together (see FIGS.20-22 ). Affixed to the inboard face of each gear segment of segmentedgear 214A is a pin 217. Each gear segment of segmented gear 214Aincludes a hinge portion 215 coupled to a hinge receiver 258 disposed onlayshaft 216. Hinge receiver 258 may be unitary with layshaft 216 or maybe affixed by a suitable fastening mechanism (e.g., screws, frictionfit, etc.).

Third gear cluster 218 comprises a segmented gear 218A and anon-segmented sprocket 218B nestable therein (see FIGS. 23-25 ). Affixedto the inboard face of each gear segment of segmented gear 218A is a pin226. Each gear segment of segmented gear 218A includes a hinge portion219 coupled to a hinge receiver 260 disposed on layshaft 216. Hingereceivers 258 and 260 may be unitary with layshaft 216 or may be affixedby a suitable mechanism (e.g., screws, friction fit, etc.).

Third gear cluster 218 is configured to engage second chain 220. Secondchain 220 couples a selected one of the gears to fourth gear cluster222, thereby transmitting rotation of third gear cluster 218 to fourthgear cluster 222. Typically, second chain 220 directly engages a singleone of gears of third gear cluster 218 and fourth gear cluster 222 atany given time; however, the chain may engage more than one of the gearsof the clusters at some stages of operation, such as when the chain isbeing shifted from one gear to another (e.g., in response to user and/orcontroller input).

Fourth gear cluster 222 is securely mounted on output shaft 223 suchthat the output shaft rotates with the fourth gear cluster. Fourth gearcluster 222 comprises a segmented gear 222A and a non-segmented sprocket222B (see FIGS. 26-28 ). Affixed to the inboard face of each gearsegment of segmented gear 222A is a pin 227. Sprocket 222B includes anopening for mating with output shaft 223. Each gear segment of segmentedgear 222A includes a hinge portion 221 configured to mate with a hingereceiver 262 disposed on layshaft 216. Hinge receiver 258 may be unitarywith layshaft 216 or may be attached by a suitable mechanism (e.g.,screws, friction fit, etc.).

Hollow output shaft 223 (AKA an output sleeve) surrounds and is coaxialwith spindle 206 (see. FIG. 12 ), such that the output shaft and thespindle are freely able to rotate independently of one another. Outputshaft 223 is affixed to chainring 224 (e.g., by a spider), such that thechainring rotates with the output shaft independently of the spindle.Chainring 224 thus transmits power from gearbox 200 to an externalsystem, typically a rear wheel of a bicycle or another suitable wheel orvehicle.

FIG. 12 depicts a sectional view of the gearing system of gearbox 200taken at line 12-12 of FIG. 3 . Crankarm 204 is coupled to spindle viacrank screw 205. Output shaft 223 is situated coaxially on an end ofspindle 106 and rotationally isolated from the spindle by bearings 225Aand 2258.

Disposed at one end of spindle 206 is a flange 206A and disposed at theopposite end, encircling output shaft 223 is a flange 206B. Spindle 206is rotationally isolated from flange 206A via bearing 207A, andsimilarly, output shaft 223 is rotationally isolated from flange 206Bvia bearing 207B.

Similarly, disposed at one end of layshaft 216 is a flange 216A anddisposed at the opposite end is a flange 2168. Layshaft 216 isrotationally isolated from flange 216A via bearing 117A, and similarly,layshaft 216 is rotationally isolated from flange 216B via bearing 117B.

FIGS. 13 and 14 show layshaft 216 with gear clusters 214 and 218 removedand coupled, respectively. As shown in FIGS. 13 and 14 , sprocket 214Bmates with layshaft 216 in the space between hinge receiver 258 andflange 216A. Similarly, sprocket 2188 mates with layshaft 216 in thespace between hinge receiver 260 and flange 2168. FIGS. 17-28 depictvarious views of portions of the gear clusters described above.

FIGS. 15 and 16 show an exploded view and partial exploded view,respectively, of spindle 206 and output shaft 223 with variouscomponents for attachment thereon.

As shown in FIGS. 17-19 , first gear cluster 208 comprises a pluralityof segmented gears having different diameters. In the current example,first gear cluster 208 comprises two gears (one inboard and oneoutboard). In another example, the first gear cluster may comprise moreor fewer gears. Gears are arranged within first gear cluster 208 fromlargest-diameter gear to smallest-diameter gear. Each segment of thesegmented gear 208A shares a hinge with a corresponding segment ofsegmented gear 208B.

As shown in FIGS. 20-22 , second gear cluster 214 comprises a sprocketor cog (e.g., a single non-segmented gear) having a first diameter and asegmented gear having a second (larger) diameter, the segmented gearbeing capable of transitioning into and out of the same plane as thesmaller sprocket.

As shown in FIGS. 23-25 , third gear cluster 218 includes anon-segmented cog or sprocket having a first diameter and a segmentedgear having a second (larger) diameter, the segmented gear being capableof transitioning into and out of the same plane as the smaller sprocket.

As shown in FIGS. 26-28 , fourth gear cluster 222 comprises a cog havinga first diameter and a segmented gear having a second (larger) diameter,the segmented gear being capable of transitioning into and out of thesame plane as the smaller sprocket.

FIG. 29 shows the engagement of portions of shifting system 210 withgear clusters 208 and 222. As shown in the figure, the shift wedgecorresponding to gear cluster 208 is in its second position and the gearsegments of gear 208B are in their pivoted position. Accordingly, thegear segments of gear 208A are in their coplanar position. In contrast,the shift wedge corresponding to gear cluster 222 is in its firstposition and the gear segments of gear 222A are in their pivotedposition.

In the current example, gearbox 200 includes two gear options for firstgear cluster 208, corresponding to gears 208A and 208B. These optionsmay be identified as A1 and A2, respectively. In the current example,gearbox 200 includes two gear options for second gear cluster 214,corresponding to gears 214A and 214B. These options may be identified asB1 and B2, respectively. In the current example, gearbox 200 includestwo gear options for third gear cluster 218, corresponding to gears 218Aand 218B. These options may be identified as C1 and C2, respectively. Inthe current example, gearbox 200 includes two gear options for fourthgear cluster 222, corresponding to gears 222A and 222B. These optionsmay be identified as D1 and D2, respectively.

A combination of any one of the gear options of the first gear cluster208, any one of the gear options of second gear cluster 214, any one ofthe gear options for third gear cluster 218, and any one of the gearoptions for fourth gear cluster 222 determines a gear ratio of gearbox200. Each combination of the available options may be referred to as a“gear” and/or “speed” of the vehicle that includes gearbox 200.

An operator of the vehicle may switch between gear ratios by switchingany of the selected options to another available option. For example, ifthe selected options are presently A1, B1, C2, and D2, the operator maychange the present gear ratio by switching D2 to D1. Alternatively, oradditionally, the operator may change A1 to A2, and/or may change C2 toC1. Switching gear ratios is typically achieved by actuating amechanical and/or electronic control to pivot the gear segments of asegmented gear, thereby engaging the chain with a different gear.

C. Illustrative Belt-Driven Gearing System

This section describes a belt-driven gearing system 300 for use withgearboxes of the present disclosure. See FIGS. 30-43 .

The components and configurations described in this section may beutilized in gearboxes such as gearbox 200, described above, assubstitutions and/or additions to the components and configurationsalready described with respect to gearbox 200. The components describedin this section may be utilized in gearbox 200, e.g., as a replacementfor the corresponding components described above. For example, one ormore of the belt-driven gear clusters described in this section may beutilized in gearboxes 200 and/or 400 in place of the correspondingchain-engaging gear clusters described herein (e.g., gear clusters 208,214, 218, and/or 222), and/or with system 510.

With continuing reference to FIGS. 30-43 , belt-driven gearing system300 includes: a first gear cluster 308 configured to be disposed onspindle 206, a second gear cluster 314 configured to be disposed onlayshaft 216, a third gear cluster 318 configured to be disposed onlayshaft 216, and a fourth gear cluster 322 configured to be disposed onoutput shaft 223. First gear cluster 308 is coupled to second gearcluster 314 by a first belt 312. Similarly, third gear cluster 318 iscoupled to fourth gear cluster 322 by a second belt 320.

Accordingly, rotation of spindle 206 (e.g., by a bicycle rider operatingpedals attached to the crankarms and/or by a motor) transmits power fromfirst gear cluster 308 via first belt 312 to second gear cluster 314,and from the second gear cluster via the layshaft to third gear cluster318. Second belt 320 transmits power from third gear cluster 318 tofourth gear cluster 322, and power is transmitted from the fourth gearcluster via output shaft 223 to chainring 224, and/or to anothersuitable system.

In the example shown in FIGS. 30 and 31 , first and second belts 312,320 are toothed belts (AKA timing belts), although other ridged orcastellated belts may be utilized. In this example, each belt has atoothed surface and a non-toothed surface. In some examples, frictionbelts are utilized, e.g., flat belts, V-belts, ribbed belts (i.e.,poly-V belts), hexagonal belts, etc., with gears of the system having acorresponding profile to engage the selected belt. As each type of beltprovides a different response with respect to maximum torque, slippage,etc., suitable belts may be selected based on the expected applicationand load.

In the example shown in FIGS. 30-43 , gear clusters 308, 314, 318, 322are configured to engage the timing belts. In other words, the gearclusters include a plurality of complimentary castellations configuredto engage the toothed surfaces of belts 312, 320. In some examples, thegear clusters are adapted to engage a friction belt, e.g., by having aprofile or contour complimentary to that of the friction belt.

Each of the gear clusters may include a plurality of gears, one or moreof which have a plurality of gear segments. Gears that have gearsegments may be referred to as segmented gears. Each gear segment may beshaped as an annular sector. In some examples, each segmented gearcomprises four gear segments. Each gear segment is rotatably attached toa hinge disposed near the center of the segmented gear. One or more gearclusters may have a non-segmented sprocket having a smaller diameterthan the respective segmented gear. Each gear segment may be attached toa shifting pin. Each gear segment pivots (or folds) in a directiontransverse to the plane of the gear. In other words, each such gearsegment is transitionable between a coplanar position and a pivoted (AKAfolded) position. This configuration enables a segmented gear totransition (e.g., stepwise) between a coplanar configuration (i.e., withall segments aligned to form a substantially coplanar gear) and apivoted (AKA pyramidal) configuration (i.e., with all gear segmentsrotationally skewed in the same direction away from the plane formed inthe coplanar configuration).

The shifting of gear clusters 308, 314, 318, and 322 is substantiallysimilar to the shifting of gear clusters 208, 214, 218, and 222, e.g.,utilizing shifting system 210 as described above or shifting system 510described below.

As shown in FIG. 30 , third gear cluster 318 is configured to engagesecond belt 320. Second belt 320 couples a selected one of the gears tofourth gear cluster 322, thereby transmitting rotation of third gearcluster 318 to fourth gear cluster 322. Typically, second belt 320directly engages a single one of the gears of third gear cluster 318 andfourth gear cluster 322 at any given time; however, the belt may engagemore than one of the gears of the clusters at some stages of operation,such as when the belt is being shifted from one gear to another (e.g.,in response to user and/or controller input). Fourth gear cluster 322may be securely mounted on output shaft 223 (see above) such that theoutput shaft rotates with the fourth gear cluster.

As shown in FIG. 30 , gearing system 300 includes a first belt tensioner332. First belt tensioner 332 includes at least one idler 336 having afixed location, at least one stationary gear 337 attached to a mountingbracket 339, and at least one adjustable gear 338 configured to be movedor translated by a pushrod 340. In the example shown in FIG. 30 , firstbelt tensioner 332 includes two idlers. Idlers 336 have a smooth outersurface configured to engage the smooth, non-toothed side or surface ofbelt 320. Conversely, stationary gear 337 and adjustable gear 338 havecastellations configured to engage the toothed surface of belt 320. Aspring is coaxially mounted to pushrod 340 to provide a biasing force.

First belt tensioner 332 may be configured to engage any of the beltsdescribed above. In the current example, idler 336 and gears 337, 338 offirst belt tensioner 332 are configured to engage belt 320. Accordingly,belt 320 interfaces with third gear cluster 318, fourth gear cluster322, and belt tensioner 332.

First belt tensioner 332 is configured such that pushrod 340 can beutilized to linearly displace gears 338 with respect to gear 337,thereby applying more or less tension to the engaged belt. Manipulationof pushrod 340 may be manual (e.g., by a user), and/or may be automatic(e.g., using mechanical and/or electric components).

As shown in FIG. 31 , first gear cluster 308 is coupled to second gearcluster 314 by first belt 312. The system is configured such that firstbelt 312 directly engages a single one of the gears of first gearcluster 308 and second gear cluster 314 at any given time; however, thebelt may partially engage more than one of the gears of each cluster atsome stages of operation, such as when the belt is being segmentallyshifted from one gear to another (e.g., in response to user and/orcontroller input). Second gear cluster 314 is securely mounted onlayshaft 216 (see above) such that rotation of second gear cluster 314also rotates the layshaft.

Additionally, as shown in FIG. 31 , gearing system 300 includes a secondbelt tensioner 334. Second belt tensioner 334 is configured to engagefirst belt 312. Accordingly, belt 312 is configured to interface withfirst gear cluster 308, second gear cluster 314, and belt tensioner 334.

In the example shown in FIG. 31 , belt tensioner 334 includes a singleidler 342 and an adjustable gear 344 attached to a pushrod 346. Idler342 has a smooth outer surface configured to engage the non-toothedsurfaced of belt 312. Conversely, adjustable gear 338 includescastellations configured to engage the toothed surface of belt 312. Aspring is coaxially mounted to pushrod 340 to provide a biasing force.

Second belt tensioner 334 is configured such that pushrod 346 can beutilized to displace gear 344, thereby applying more or less tension tothe engaged belt. Manipulation of pushrod 346 may be manual (e.g., by auser), and/or may be automatic (e.g., using mechanical and/or electriccomponents).

As shown in FIGS. 32-34 , first gear cluster 308 comprises a sprocket orcog 308B (e.g., a single non-segmented gear) having a first diameter anda segmented gear 308A having a second (larger) diameter. The segmentedgear is capable of transitioning into and out of the same plane as thesmaller sprocket. In the current example, first gear cluster 308comprises two gears. In another example, the first gear cluster maycomprise more or fewer gears. Gears are arranged within first gearcluster 308 from largest-diameter gear to smallest-diameter gear.

Each gear segment of segmented gear 308A includes a pin (e.g., pin 211)affixed in the same corresponding location as segmented gear 208A,described above. Additionally, each gear segment of segmented gear 308Ais configured to include a hinge portion (e.g., hinge portion 209) inthe same corresponding location as segmented gear 208A. The hingeportion is configured to mate with hinge receiver 256 disposed onspindle 206.

As shown in FIGS. 35-37 , second gear cluster 314 has a nestedarrangement, such that a segmented gear 314A and a non-segmentedsprocket 314B are nestable together. The segmented gear being capable oftransitioning into and out of the same plane as the smaller sprocket. Inthe depicted example, second gear cluster 314 comprises two gears. Inanother example, the second gear cluster may comprise more or fewergears. Gears are arranged within second gear cluster 314 fromlargest-diameter gear to smallest-diameter gear.

The inboard face of each gear segment of segmented gear 314A isconfigured to include a pin (e.g., pin 217) affixed in the samecorresponding location as segmented gear 214A. Additionally, each gearsegment of segmented gear 314A is configured to include a hinge portion(e.g., hinge portion 215) in the same corresponding location assegmented gear 214A. The hinge portion is configured to mate with hingereceiver 258 disposed on layshaft 216.

As shown in FIG. 38-43 , third gear cluster 318 has a nestedarrangement, such that a segmented gear 318A and a non-segmentedsprocket 3188 are nestable together. The segmented gear being capable oftransitioning into and out of the same plane as the smaller sprocket. Inthe current example, third gear cluster 318 comprises two gears. Inanother example, the third gear cluster may comprise more or fewergears. Gears are arranged within third gear cluster 318 fromlargest-diameter gear to smallest-diameter gear.

The inboard face of each gear segment of segmented gear 318A includes apin (e.g., pin 226) affixed in the same corresponding location assegmented gear 218A. Additionally, each gear segment of segmented gear318A is configured to include a hinge portion (e.g., hinge portion 219)in the same corresponding location as segmented gear 218A. The hingeportion is configured to be coupled to hinge receiver 260 disposed onlayshaft 216.

As shown in FIG. 41-43 , fourth gear cluster 322 has a nestedarrangement, such that a segmented gear 322A and a non-segmentedsprocket 322B are nestable together. The segmented gear being capable oftransitioning into and out of the same plane as the smaller sprocket. Inthe current example, fourth gear cluster 322 comprises two gears. Inanother example, the fourth gear cluster may comprise more or fewergears. Gears are arranged within third gear cluster 318 fromlargest-diameter gear to smallest-diameter gear.

The inboard face of each gear segment of segmented gear 322A has a pin(e.g., pin 227) affixed in the same corresponding location as segmentedgear 222A. Sprocket 322B includes an opening for mating with outputshaft 223. Each gear segment of segmented gear 322A is configured toinclude a hinge portion (e.g., hinge portion 221). The hinge portion isconfigured to mate with hinge receiver 262 disposed on layshaft 216. Inthe depicted example, gearing system 300 includes two gear options forfirst gear cluster 308, corresponding to gears 308A and 308B. Theseoptions are identified as A1 and A2, respectively. In the currentexample, gearing system 300 includes two gear options for second gearcluster 314, corresponding to gears 314A and 314B. These options areidentified as B1 and B2, respectively. In the current example, gearingsystem 300 includes two gear options for third gear cluster 318,corresponding to gears 318A and 318B. These options are identified as C1and C2, respectively. In the current example, gearing system 300includes two gear options for fourth gear cluster 322, corresponding togears 322A and 322B. These options are identified as D1 and D2,respectively.

A combination of any one of the gear options of the first gear cluster308, any one of the gear options of second gear cluster 314, any one ofthe gear options for third gear cluster 318, and any one of the gearoptions for fourth gear cluster 322 determines a gear ratio of gearingsystem 300. Each combination of the available options may be referred toas a “gear” and/or “speed” of the vehicle that includes gearbox 300.

An operator of the vehicle may switch between gear ratios by switchingany of the selected options to another available option. For example, ifthe selected options are presently A1, B1, C2, and D2, the operator maychange the present gear ratio by switching D2 to D1. Alternatively, oradditionally, the operator may change A1 to A2, and/or may change C2 toC1. Switching gear ratios is typically achieved by actuating amechanical and/or electronic control to pivot the gear segments of asegmented gear, thereby engaging the belt with a different gear.

D. Third Illustrative Gearbox

This section describes a gearbox 400, which is an example of gearbox 100described above. See FIGS. 44-69 .

As shown in FIGS. 44 and 45 , gearbox 400 includes a housing 402. Thehousing at least partially contains a gearing system, as describedabove. An Illustrative gearing system for gearbox 400 is describedfurther below. A spindle 406 extends through the housing. A firstcrankarm 404 and a second crankarm (not shown) are coupled to respectiveends of spindle 406, and a chainring 424 couples gearbox 400 to a wheel(e.g., a rear wheel, via an external drive chain or belt).

FIG. 4 is a top view of gearbox 400. Gearbox 400 includes a layshaft 416and four gear clusters: a first (input) gear cluster 408 (also referredto as cluster 1) disposed on a sheath 407 rotationally coupled tospindle 406, a second gear cluster 414 (also referred to as cluster 2)disposed on layshaft 416, a third gear cluster 418 (also referred to ascluster 3) disposed on layshaft 416, and a fourth gear cluster 422 (alsoreferred to as cluster 4) disposed on an output shaft 423 (AKA a drivenshaft), which is an example of output shaft 123. First gear cluster 408is coupled to second gear cluster 414 by a first chain 412. Similarly,third gear cluster 418 is coupled to fourth gear cluster 422 by a secondchain 420. Although chains are referred to herein, one or more belts(e.g., timing belts) may be used.

Accordingly, rotation of spindle 406 (e.g., by a bicycle rider operatingpedals attached to the crankarms and/or by a motor) transmits power fromfirst gear cluster 408 via first chain 412 to second gear cluster 414,and from the second gear cluster via the layshaft to third gear cluster418. Second chain 420 transmits power from third gear cluster 418 tofourth gear cluster 422, and power is transmitted from the fourth gearcluster via output shaft 423 to chainring 424.

Each of the gear clusters may include a plurality of gears, one or moregears of the plurality of gears having a plurality of gear segments.Gears that have gear segments may be referred to as segmented gears.Each gear segment may be shaped as an annular sector. In some examples,each segmented gear comprises four gear segments, although more or fewermay be present. Each gear segment is pivotably attached to a hingedisposed near the center of the segmented gear.

One or more gear clusters may include a non-segmented sprocket having asmaller diameter than the respective segmented gear. Each gear segmentpivots (or folds) in a direction transverse to the plane of the gear. Inother words, each gear segment may transition between a coplanarposition and a pivoted (AKA folded) position out of the original plane.This configuration enables the transition of a segmented gear (e.g.,stepwise) between a coplanar configuration (i.e., with all segmentsaligned to form a substantially coplanar gear) and a pivoted (AKApyramidal) configuration (i.e., with all gear segments rotationallyskewed in the same direction away from the plane formed in the coplanarconfiguration)

As shown in FIG. 46 , a shifting system 410 is disposed at withingearbox 400, in a generally central location. Shifting system 410 is anexample of shifting system 110 described above. A more detaileddescription of shifting system 410 is provided below, with respect toFIGS. 51-57 . Alternatively, shifting system 510 may be utilized, adetailed description of shifting system 510 is provided in Section Ewith respect to FIGS. 70-74 below.

As shown in FIG. 47 , gearbox 400 includes a first chain tensioner 432.First chain tensioner 432 includes at least one idler 436 having a fixedlocation, at least one idler 437 attached to an adjustable mountingbracket 439, and at least one adjustable gear 438 configured to be movedor translated by a pushrod 440. In the example shown in FIG. 47 , firstchain tensioner 432 includes two idlers. A spring is coaxially mountedto pushrod 440 to provide a biasing force.

First chain tensioner 432 may be configured to engage any of the chainsdescribed above. In the current example, idlers 436, 437 and gear 438 offirst chain tensioner 432 are configured to engage chain 420.Accordingly, chain 420 interfaces with third gear cluster 418, fourthgear cluster 422, and chain tensioner 432.

First chain tensioner 432 is configured such that pushrod 440 can beutilized to linearly displace gears 438 with respect to idler 437,thereby applying more or less tension to the engaged chain. Manipulationof pushrod 440 may be manual (e.g., by a user), and/or may be automatic(e.g., using mechanical and/or electric components).

As shown in FIG. 48 , first gear cluster 408 is coupled to second gearcluster 414 by first chain 412. The system is configured such that firstchain 412 directly engages a single one of the gears of first gearcluster 408 and second gear cluster 414 at any given time; however, thechain may partially engage more than one of the gears of each cluster atsome stages of operation, such as when the chain is being segmentallyshifted from one gear to another (e.g., in response to user and/orcontroller input). Second gear cluster 414 is securely mounted onlayshaft 416 (see above) such that rotation of second gear cluster 414also rotates the layshaft.

Additionally, as shown in FIG. 48 , gearbox 400 includes a second chaintensioner 434. Second chain tensioner 434 is configured to engage firstchain 412. Accordingly, chain 412 is configured to interface with firstgear cluster 408, second gear cluster 414, and chain tensioner 434.

In the example shown in FIG. 48 , chain tensioner 434 includes an idler442, a stationary gear 443, and an adjustable gear 444 attached to apushrod 446. A spring is coaxially mounted to pushrod 446 to provide abiasing force.

Second chain tensioner 434 is configured such that pushrod 446 can beutilized to displace gear 444, thereby applying more or less tension tothe engaged chain. Manipulation of pushrod 446 may be manual (e.g., by auser), and/or may be automatic (e.g., using mechanical and/or electriccomponents).

As shown in the sectional view of FIG. 49 , gearbox 400 includes a spragclutch 447 disposed coaxially between spindle 406 and sheath 407. Spragclutch 447 is configured such that forward rotation of spindle 406(e.g., by the pedaling of a user) causes a rotation of sheath 407 andthereby rotates first gear cluster 408. Conversely, sprag clutch 447enables spindle 406 to freely rotate backwards without engaging sheath407. In other words, sprag clutch 447 enables a user to pedal backwardswithout causing the gear clusters to similarly rotate backwards.

FIG. 50 depicts a sectional view of the gearing system of gearbox 400taken at line 8-8 of FIG. 45 . Crankarm 404 is coupled to spindle viacrank screw 405. Output shaft 423 is situated coaxially on an end ofspindle 406 and rotationally isolated from the spindle by bearings 425.

Disposed at one end of spindle 406 is a flange 406A and disposed at theopposite end, encircling output shaft 423 is a flange 406B. Spindle 406is rotationally isolated from flange 406A via bearing 407A, andsimilarly, output shaft 423 is rotationally isolated from flange 406Bvia bearing 407B.

Similarly, disposed at one end of layshaft 416 is a flange 416A anddisposed at the opposite end is a flange 4168. Layshaft 416 isrotationally isolated from flange 416A via bearing 417A, and similarly,layshaft 416 is rotationally isolated from flange 416B via bearing 417B.

In the current example, first gear cluster 408 comprises two segmentedgears, 408A and 408B. Affixed to each gear segment of segmented gear408A is a hinge knuckle 411. Each gear segment of segmented gear 408Aadditionally shares a common hinge portion 409 with a corresponding gearsegment of segmented gear 408B, in a fixed angular relationship. Hingeportion 409 is configured to mate with a hinge receiver 456 disposed onsheath 407. Hinge receiver 456 may be unitary with sheath 407 or may beaffixed by a suitable mechanism (e.g., screws, friction fit, etc.).Corresponding segments of the two gears are configured to pivottogether, rather than independently (see FIGS. 58-60 ). In other words,when a segment of gear 408A is shifted out of the plane of chain 412,the corresponding segment of 408B is brought into the plane of chain 412(thereby engaging the chain).

First gear cluster 408 is coupled to second gear cluster 414 by firstchain 412. The system is configured such that first chain 412 directlyengages a single one of the gears of first gear cluster 408 and a singleone of the gears of second gear cluster 414 at any given time; however,the chain may partially engage more than one of the gears of eachcluster at some stages of operation, such as when the chain is beingsegmentally shifted from one gear to another (e.g., in response to userand/or controller input).

Second gear cluster 414 is securely mounted on layshaft 416 such thatrotation of second gear cluster 414 also rotates the layshaft. Secondgear cluster 414 has a nested arrangement, such that a segmented gear414A and a non-segmented sprocket 414B are nestable together (see FIGS.61-21 ). Sprocket 414B mates with layshaft 416 in the space betweenhinge receiver 458 and flange 416A. Similarly, sprocket 4188 mates withlayshaft 416 in the space between hinge receiver 460 and flange 4168.Affixed to the inboard face of each gear segment of segmented gear 414Ais a hinge knuckle 417. Each gear segment of segmented gear 414Aincludes a hinge portion 415 coupled to a hinge receiver 458 disposed onlayshaft 416. Hinge receiver 458 may be unitary with layshaft 416 or maybe affixed by a suitable fastening mechanism (e.g., screws, frictionfit, etc.).

Third gear cluster 418 comprises a segmented gear 418A and anon-segmented sprocket 4188 nestable therein (see FIGS. 64-24 ). Affixedto the inboard face of each gear segment of segmented gear 418A is ahinge knuckle 426. Each gear segment of segmented gear 418A includes ahinge portion 419 coupled to a hinge receiver 460 disposed on layshaft416. Hinge receivers 458 and 460 may be unitary with layshaft 416 or maybe affixed by a suitable mechanism (e.g., screws, friction fit, etc.).

Third gear cluster 418 is configured to engage second chain 420. Secondchain 420 couples a selected one of the gears to fourth gear cluster422, thereby transmitting rotation of third gear cluster 418 to fourthgear cluster 422. Typically, second chain 420 directly engages a singleone of gears of third gear cluster 418 and fourth gear cluster 422 atany given time; however, the chain may engage more than one of the gearsof the clusters at some stages of operation, such as when the chain isbeing shifted from one gear to another (e.g., in response to user and/orcontroller input).

Fourth gear cluster 422 is securely mounted on output shaft 423 suchthat the output shaft rotates with the fourth gear cluster. Fourth gearcluster 422 comprises a segmented gear 422A and a non-segmented sprocket422B (see FIGS. 65-27 ). Affixed to the inboard face of each gearsegment of segmented gear 422A is a hinge knuckle 427. Sprocket 422Bincludes an opening for mating with output shaft 423. Each gear segmentof segmented gear 422A includes a hinge portion 421 configured to matewith a hinge receiver 462 disposed on output shaft 423. Hinge receiver462 may be unitary with output shaft 423 or may be attached by asuitable mechanism (e.g., screws, friction fit, etc.).

Hollow output shaft 423 (AKA an output sleeve) surrounds and is coaxialwith spindle 406, such that the output shaft and the spindle are freelyable to rotate independently of one another. Output shaft 423 is affixedto chainring 424 (e.g., by a spider), such that the chainring rotateswith the output shaft independently of the spindle. Chainring 424 thustransmits power from gearbox 400 to an external system, typically a rearwheel of a bicycle or another suitable wheel or vehicle.

Gearbox 400 utilizes a shifting system for transitioning the segmentedgears between the coplanar configuration and the pivoted configuration.In general, gearbox 400 may utilize shifting system 410 describedimmediately below, or any other suitable system, such as shifting system510 described in Section C with respect to FIGS. 70-74 .

Turning now to FIG. 51 , shifting system 410 is depicted. Shiftingsystem 410 includes a plurality of actuators 448 and a plurality oftoggles 450, each of the actuators and toggles coupled to a mountingplate 449. Mounting plate 449 is disposed at a central location ingearbox 400, such that one actuator and one toggle correspond to each ofthe four gear clusters. Each actuator 448 may include a respectivelinear actuator (e.g., under control of an electronic controller and/ora user) coupled to a pivoting actuator arm.

As shown in FIGS. 52 and 53 , actuator 448 is configured to engage andmanipulate toggle 450. Toggle 450 is configured to selectively andmechanically interface with portions of a plurality of shifting sliders451 seated within a guiding plate 453. Each shifting slider is coupledto a gear segment of each of the segmented gears (e.g., segmented gears408A, 414A, 418A, and 422A).

Shifting slider 451 includes a pair of protrusions referred to herein asfirst protrusion 452 and second protrusion 454, generally configuredsuch that rotation of the corresponding gear cluster causes the shiftingslider 451 to rotate, thus bringing first and second protrusions 452,454 to opposing sides of toggle 450. Actuator 448 is configured toselectively transition between two positions, e.g., by way of a linearactuator under control of an electronic controller, thereby causingtoggle 450 rotate, by way of lever 461, between two correspondingpositions—one position for each of first and second protrusions 452,454. The two positions of toggle 450 are herein referred to as a firstposition and a second position.

When toggle 450 is in the first position, rotation of the gear cluster(and therefore guiding plate 453 and shifting slider 451) causes toggle450 to strike first protrusion 452 thereby pushing shifting slider 451in a generally outward direction. Conversely, when toggle 450 is in thesecond position, rotation of the gear cluster causes toggle 450 tostrike second protrusion 454 thereby pushing shifting slider 451 in agenerally inward direction. In other words, actuator 448 and toggle 450are configured to selectively transition shifting slider 451 in a radialdirection between two positions, e.g., along the arrow in FIG. 11 .

A retention spring 459 is configured to provide a biasing force ontoggle 450, such that toggle 450 is retained in a neutral positionresting against lever 461 when toggle 450 is not engaging first orsecond protrusions 452, 454. Retention spring 459 and toggle 450 areconfigured such that the neutral position of toggle 450 corresponds tothe toggle being between generally between first and second protrusions452, 454. In the neutral position, toggle 450 does not engage (i.e.,strike) either the first or second protrusions. In other words, whentoggle 450 is in the neutral position, the gear ratio of thecorresponding gear cluster is not changed. Additionally, retentionspring 459 enables toggle 450 to stay generally immobile when gearbox400 is agitated or otherwise jolted.

After shifting slider 451 is transitioned to either of the twopositions, the protrusions pass toggle 450 and the biasing force ofretention spring 459 returns toggle 450 to the neutral position. Asshown in FIGS. 54 and 55 , each shifting slider 451 is coupled to a gearsegment of the segmented gears. The linear translation of shiftingslider 451 between the two positions causes the respective gear segmentto rotate between the coplanar and pivoted positions described above. Inthe example depicted in FIGS. 51-55 , the first position of toggle 450corresponds to the coplanar position of the segmented gears.Accordingly, the second position of toggle 450 corresponds to thepivoted position of the segmented gears.

As shown in FIGS. 56 and 57 , each shifting slider 451 is coupled to ahinge 455 having a hinge pin 457. Shifting slider 451 and hinge 455 havea fixed relationship such that linear translation of shifting slider 451causes rotation of hinge 455. Each hinge knuckle of the correspondinggear segments (i.e., hinge knuckles 411, 417, 426, 427) is configured tocouple to hinge pin 457. This configuration enables the transition ofthe segmented gears between the coplanar and pivoted positions by thetranslation of the shifting slider as described above.

FIGS. 58-69 depict the first, second, third, and fourth gear clusters inisolation.

As shown in FIGS. 58-60 , first gear cluster 408 comprises a pluralityof segmented gears having different diameters. In the current example,first gear cluster 408 comprises two gears (one inboard and oneoutboard). In another example, the first gear cluster may comprise moreor fewer gears. Gears are arranged within first gear cluster 408 fromlargest-diameter gear to smallest-diameter gear. Each segment of thesegmented gear 408A shares a hinge with a corresponding segment ofsegmented gear 408B.

As shown in FIGS. 61-63 , second gear cluster 414 comprises a sprocketor cog (e.g., a single non-segmented gear) having a first diameter and asegmented gear having a second (larger) diameter, the segmented gearbeing capable of transitioning into and out of the same plane as thesmaller sprocket.

As shown in FIGS. 64-66 , third gear cluster 418 includes anon-segmented cog or sprocket having a first diameter and a segmentedgear having a second (larger) diameter, the segmented gear being capableof transitioning into and out of the same plane as the smaller sprocket.

As shown in FIGS. 65-69 , fourth gear cluster 422 comprises a cog havinga first diameter and a segmented gear having a second (larger) diameter,the segmented gear being capable of transitioning into and out of thesame plane as the smaller sprocket.

In the current example, gearbox 400 includes two gear options for firstgear cluster 408, corresponding to gears 408A and 408B. These optionsmay be identified as A1 and A2, respectively. In the current example,gearbox 400 includes two gear options for second gear cluster 414,corresponding to gears 414A and 414B. These options may be identified asB1 and B2, respectively. In the current example, gearbox 400 includestwo gear options for third gear cluster 418, corresponding to gears 418Aand 418B. These options may be identified as C1 and C2, respectively. Inthe current example, gearbox 400 includes two gear options for fourthgear cluster 422, corresponding to gears 422A and 422B. These optionsmay be identified as D1 and D2, respectively.

A combination of any one of the gear options of the first gear cluster408, any one of the gear options of second gear cluster 414, any one ofthe gear options for third gear cluster 418, and any one of the gearoptions for fourth gear cluster 422 determines a gear ratio of gearbox400. Each combination of the available options may be referred to as a“gear” and/or “speed” of the vehicle that includes gearbox 400.

An operator of the vehicle may switch between gear ratios by switchingany of the selected options to another available option. For example, ifthe selected options are presently A1, B1, C2, and D2, the operator maychange the present gear ratio by switching D2 to D1. Alternatively, oradditionally, the operator may change A1 to A2, and/or may change C2 toC1. Switching gear ratios is typically achieved by actuating amechanical and/or electronic control to pivot the gear segments of asegmented gear, thereby engaging the chain with a different gear.

E. Illustrative Shifting System

This section describes a shifting system 510. See FIGS. 70-74 . Shiftingsystem 510 is configured to be utilized in gearbox 100, gearbox 200and/or gearbox 400 as a direct replacement for shifting system 110,shifting system 210 and shifting system 410, respectively. Shiftingsystem 510 is analogous to shifting system 410, with differencesdescribed below. Additionally, or alternatively, shifting system 510 maybe utilized with any drivetrain including a pivoting segmented gearand/or segmented gear cluster (i.e., independent of a gearbox). Forexample, shifting system 510 may be utilized in the drivetrain of abicycle, electric bicycle, or motorcycle having one or more segmentedchainrings and/or cassette cogs.

The shifting system includes a pivoting toggle configured to interactwith a respective segment actuator of each of the segments of theinboard gear of a given gear cluster. This toggle causes each of thesegments of the gear to selectively transition into and out of the planeof the belt or chain, such that the belt or chain is switched to adifferent gear (e.g., having a different diameter) without displacingthe belt or chain out of its plane. In this example, the toggle isselectively pivoted using a linear actuator and lever arm, althoughother methods may be utilized. The segment actuators rotate with thesegmented gear, while the toggle does not, instead pivoting about anaxis that is stationary with respect to the rotating gear.

In the present example, each segment actuator includes a sliderconfigured to translate radially in a guide plate that rotates with thegear cluster, the slider being coupled to the respective gear segment bya slip joint or slotted hinge mechanism. Radial translation of theslider is caused when one or more pegs or protrusions of the sliderrotate into contact with the toggle, and a ramped face or edge of thetoggle urges the peg (and therefore the slider) in a radial direction.Because the slider is connected to the segment by the slotted hinge,this translation causes the segment to pivot on its pivot axis (seeFIGS. 71-74 ).

As with other shifting systems described herein, the toggle is disposedsuch that each segment actuator interfaces with (and is repositioned by)the toggle at a rotational position that pivots the segment when thesegment is unloaded, i.e., not encumbered by the belt or chain.Furthermore, the toggle in this example need not be repositioned betweensegment actuations or after all segments have been pivoted into or outof the plane. The toggle simply remains in its existing configurationuntil further pivoting of the segments is called for. Accordingly, eachgear cluster may be operated without a need for position sensors orother methods of ascertaining the rotational position of the gearcluster or of the tilted state of the gear segments.

Shifting system 510 includes one or more actuators 548 coupled to amounting plate and one or more toggles 550 (also referred to as wedges)manipulated by the actuators to cause shifting of the gear segments. Insome examples, the mounting plate is disposed at a central location ingearbox 500, such that one actuator corresponds to each of the four gearclusters (e.g., see FIG. 46 and corresponding mounting plate 449 above).Each actuator 548 may include any suitable actuator configured to shiftthe associated toggle between two or more positions, as described below.In the present example, actuator 548 includes a linear actuator (e.g.,under control of an electronic controller and/or a user) coupled to thetoggle by a pivoting lever 561. In some examples, actuator 548 is anelectro-mechanical linear actuator. Actuator 548 may include apiezoelectric linear actuator, a screw-type actuator, a cylinder andpiston, a step motor, a pneumatic actuator, and/or the like.

As shown in FIG. 70 , actuator 548 is configured to engage andmanipulate toggle 550 via lever 561. Toggle 550 and lever 561 pivot orrotate together about a fixed pivot 555, such that extending andretracting actuator 548 causes toggle 550 to transition between twooperative positions. In some examples, toggle 550 and lever 561 areunitary and/or formed as a single piece. In some examples, toggle 550and lever 561 are coupled together, e.g., by way of a third structure.Toggle 550 is configured to selectively mechanically interface withcorresponding portions of a plurality of shifting sliders 551 seatedwithin a rotating guiding plate 553, as described further below. Pivot555 has an axis of rotation generally parallel to the axis of rotationof the guiding plate.

Turning to FIGS. 71 and 72 , system 510 is shown in FIG. 71 with toggle550 in a first configuration or position, and in FIG. 72 with toggle 550in a second configuration or position. Toggle 550 includes a pair oframped faces referred to herein as a first ramped face 556 and a secondramped face 558. In the example depicted in FIGS. 71 and 72 , toggle 550has an asymmetrical lobe profile with lateral edges generally configuredto have a curvilinear contour, in which opposing edges form the firstand second faces. In operation, the extension of linear actuator 548along the direction indicated by arrow A causes lever 561 and toggle 550to pivot about fixed pivot 555, thereby causing a change in the positionand orientation of toggle 550 (and therefore first and second faces 556,558).

Fixed pivot 555 may be rotatably fixed to the mounting plate, a housingof the gearbox, or both, such that the pivot remains at a fixed locationin the gearbox, even when other components (such as guiding plate 553)are rotated. Toggle 550 may be selectively positioned in this mannerinto one of two states, herein referred to as a first state and a secondstate. For reference, toggle 550 is shown in its first state in FIG. 71and its second state in FIG. 72 .

Each shifting slider 551 includes a pair of protrusions, firstprotrusion 552 and second protrusion 554, manipulated by the toggle tooperably translate the shifting slider in the direction indicated byarrow C. First and second protrusions 552, 554 disposed at distallyopposite locations on the slider such that the first and secondprotrusions are brought to opposing sides of toggle 550 as the gearcluster is rotated in the direction indicated by arrow B. First andsecond protrusions 552, 554 and shifting slider 551 may be unitaryand/or formed as a single piece. In some examples, the shifting sliderand protrusions comprise a durable plastic (e.g., polyethylene,polyvinyl chloride (PVC), polyethylene terephthalate (PET), etc.),metal/metallic alloy (aluminum, titanium, steel, etc.), and/or anothersuitably durable material.

Similar to the description in Section D, with respect to FIGS. 52-57 ,each shifting slider 551 is coupled to a hinge of a respective gearsegment of each of the segmented gears (e.g., segmented gears 408A,414A, 418A, and 422A of gearbox 400). Each shifting slider 551 andrespective gear segment have a defined relationship such that lineartranslation of shifting slider 551 causes a pivot of the gear segment,described in more depth below with respect to FIGS. 73, 74 . Theshifting slider and the hinge mechanism may be collectively referred toas a segment actuator or an actuator of the gear segment.

This enables the transition of the segmented gear between the coplanarand pivoted configurations via the translation of the shifting sliders.Accordingly, the shifting sliders may be selectively transitionedbetween a first position, corresponding to the coplanar configuration ofthe segmented gear, and a second position, corresponding to the pivotedconfiguration of the segmented gear. For reference, the shifting slidersare shown in the first position in FIG. 71 and the second position inFIG. 72 .

A description of shifting system 510 causing the selective transitioningof the segmented gear between its two configurations (coplanar andpivoted) is now provided.

Consider shifting sliders 551 in their second position and toggle 550 inits first state. In this configuration, toggle 550 is oriented such thatfirst face 556 is in the path of first protrusion 552. A rotation of thegear cluster (e.g., by a user) in the direction indicated by arrow Bthereby causes first protrusion 552 to strike first face 556 causingshifting slider 551 to translate in a generally outward direction alongthe path indicated by arrow C. In some examples, protrusion 552 followsthe contour of face 556, in the manner of a cam and follower mechanism,thereby guiding slider 551 outwards gently, so as to not cause anyunnecessary force on the slider or the toggle.

As the gear cluster continues to rotate, the first protrusion of eachsubsequent slider 551 strikes first face 556 until all four of theshifting sliders have been translated outwards into their firstposition, as reflected in FIG. 71 . After all the sliders havetranslated outwards in this manner, the segmented gear has been fullyshifted into its coplanar configuration. Additionally, since the slidershave been translated outwards, the toggle is no longer in the path ofany of the first protrusions. Accordingly, the gear cluster may rotatefreely without any further shifting.

Now consider toggle 550 has been pivoted by actuator 548 into its secondstate. In this configuration, toggle 550 is oriented such that secondface 558 is in the path of second protrusion 554. A rotation of the gearcluster in the direction indicated by arrow B thereby causes secondprotrusion 554 to strike second face 558 causing shifting slider 551 totranslate in a generally inward direction along the path indicated byarrow C. In some examples, protrusion 554 follows the contour of face558, in the manner of a cam and follower mechanism.

As the gear cluster continues to rotate, the second protrusion of eachsubsequent slider 551 strikes second face 558 until all four of theshifting sliders have been translated inwards into their secondposition, as reflected in FIG. 72 . After all the sliders havetranslated inwards in this manner, the segmented gear has been fullyshifted into its pivoted configuration. Additionally, since the slidershave been translated inwards, the toggle is no longer in the path of anyof the second protrusions. Accordingly, the gear cluster may rotatefreely without any further shifting.

Turning to FIGS. 73 and 74 , the relationship between the linear motionof slider 551 and the pivoting of the corresponding gear segment is nowdescribed further. For reference, shifting slider 551 is shown in thefirst position in FIG. 73 (corresponding to FIG. 71 and the coplanarposition of the segmented gear) and shown in the second position in FIG.74 (corresponding to FIG. 72 and the pivoted position of the segmentedgear).

FIGS. 73 and 74 are side views depicting the operational engagementbetween shifting slider 551 and a single segment 559 of a segmented gearin the coplanar and pivoted positions, respectively. In the example ofFIGS. 73 and 74 , the depicted gear segment is analogous to thesegmented gear of third gear cluster 418 (i.e., segmented gear 418A),although the underlying principle is the same for each of the segmentedgears described herein.

Gear segment 559 is pivotally attached via a hinge knuckle to thelayshaft at pivot 560, defining an axis of rotation. Pivot 560corresponds to hinge pin 457 described above with respect to FIGS. 56and 57 . The gear segment is configured to rotate about this axis ofrotation between the coplanar and pivoted positions. Furthermore, thegear segment includes an extension 562 having a slot or elongatedaperture 564 formed therein. Shifting slider 551 is coupled to the gearsegment via an actuating structure disposed on an opposite side of theguiding plate 553 from toggle 550 and first and second protrusions 552and 554, by way of a pin 566 seated slidingly within aperture 564.

As shown in FIG. 74 , when shifting slider 551 is translated radiallyinward from the first position to the second position, pin 566 slideswithin aperture 564 and urges the gear segment is from the coplanarposition, rotating about the axis of rotation of pivot 560 into thepivoted position. Conversely, as shown in FIG. 73 , when shifting slider551 is translated radially outward from the second position to the firstposition, pin 566 again slides within aperture 564 and urges the gearsegment from the pivoted position into the coplanar position.

As described above, this transitioning of the gear segment is performedat a time when the segment is unloaded (i.e., free of the chain/belt),such that shifting may be performed under load without negativeconsequences. Multiple segmented sprockets of the gearbox may besimultaneously shifted in this manner, if desired.

A method describing steps for shifting a segmented gear (e.g.,describing the operation of system 510) is laid out below. Aspects ofthe gearboxes and shifting systems described above may be utilized inthe method steps described below. Although various method steps aredescribed below, the steps need not necessarily all be performed, and insome cases may be performed simultaneously or in a different order thanthe order described.

A first step includes rotating a gear cluster comprising a first gearand a coaxial second gear using a power transfer mechanism (e.g., a beltor a chain), wherein the power transfer mechanism defines a plane and iswrapped partially around the first gear, and wherein the first gear hasa plurality of gear segments independently movable (e.g., pivotable ortranslatable) into and out of the plane. In some examples, the secondgear is unsegmented. In some examples, the second gear is segmented andeach segment of the second gear has a fixed relationship with eachcorresponding segment of the first gear, such that pivoting one segmentof the first gear automatically pivots the corresponding segment of thesecond gear.

In some examples, the second gear is concentric with the first gearand/or nested within the first gear. In some examples, the teeth of thesecond gear are coplanar with teeth of the first gear.

A second step includes rotating a plurality of radially transitionablesliders in tandem with the first gear, each of the sliders having one ormore protrusions and coupled to a corresponding one of the gear segmentsof the first gear. In some examples, each of the sliders is coupled tothe corresponding one of the segments by a slotted hinge. In someexamples, the slotted hinge is on an opposite side of the slider withrespect to the one or more protrusions. In some examples, the slidersare disposed in a common guide plate disposed adjacent the first gear.

A third step includes pivoting a toggle into a first position such thata first ramped face of the toggle is in a path of the one or moreprotrusions of the sliders.

A fourth step includes sequentially moving each segment of the firstgear out of the plane of the power transfer mechanism by urging theslider radially when the one or more protrusions strike the first rampedface of the toggle, such that the power transfer mechanism wraps atleast partially around the second gear. In some examples, sequentiallymoving each segment includes pivoting each segment (e.g., on a pivotaxis) transversely (for example, orthogonally) with respect to the planeof the power transfer mechanism. Sequentially moving each segment may beperformed at a position where each segment is unloaded, i.e.,substantially free of the power transfer mechanism.

To shift the gear cluster again, a fifth step includes pivoting a toggleinto a second position such that a second ramped face of the toggle isin a path of the one or more protrusions of the sliders.

A sixth step includes sequentially moving each segment of the first gearinto the plane of the power transfer mechanism by urging the sliderradially within the guide plate when the one or more protrusions strikethe second ramped face of the toggle, such that the power transfermechanism wraps at least partially around the first gear.

F. Illustrative Chain Tensioner

This section describes an illustrative chain tensioner 600. Chaintensioner 600 is configured to be utilized in any of the gearboxesdescribed above, for example as a direct replacement for chain tensioner432 or 434. In general, chain tensioner 600 may be utilized with aroller-chain, bar-link chain, and/or other drive chains. Alternatively,chain tensioner 600 may be utilized with a belt drive or other suitablepower transmission mechanisms.

As shown in FIG. 75 , chain tensioner 600 includes first gear 602 andsecond gear 604 disposed on opposing sides of chain 606 and positivelyengaged to one another via retention bar 608. Retention bar is disposedat a fixed location in the gearbox and mounted to a rigid portion of thegearbox (e.g., mounting plate 449 of gearbox 400). In some examples,retention bar 608 had an adjustable length, such that the distancebetween first and second gears 602, 604 may be adjusted, thereby causinga change in the tension of the chain. In some examples, theangle/orientation of retention bar 608 may be adjustable to selectivelychange the tension of chain 608. In some examples, retention bar 608 mayinclude a biasing mechanism (not shown) such as a torsion spring, leafspring, etc., to increase the tension on chain 606. In some examples,the location of tension bar may be adjustable (for example, through theadjustment of one or more set screws), such that the chain tensioner maybe fine-tuned to the plane of the chain.

G. Illustrative Combinations and Additional Examples

This section describes additional aspects and features of the gearboxsystems described herein, presented without limitation as a series ofparagraphs, some or all of which may be alphanumerically designated forclarity and efficiency. Each of these paragraphs can be combined withone or more other paragraphs, and/or with disclosure from elsewhere inthis application, including the materials incorporated by reference inthe Cross-References, in any suitable manner. Some of the paragraphsbelow expressly refer to and further limit other paragraphs, providingwithout limitation examples of some of the suitable combinations.

A0. A gearbox for a vehicle, the gearbox comprising:

a drive spindle;

a first gear cluster coaxially fastened to the spindle such that thefirst gear cluster rotates with the spindle, wherein an inboard gear ofthe first gear cluster includes a plurality of pivotable inboardsegments, each of which has a respective pin protruding transverselyfrom an inboard face;

a second gear cluster having one or more gears coaxially fastened to alayshaft spaced from and parallel to the spindle, such that the layshaftrotates with the second gear cluster;

a continuous first belt or chain coupling the first gear cluster to thesecond gear cluster, such that the first gear cluster drives the secondgear cluster and the first belt or chain defines a first plane, whereinthe segments of the inboard gear of the first gear cluster are eachpivotable into and out of the first plane;

a third gear cluster having one or more gears coaxially fastened to thelayshaft and spaced from the second gear cluster, such that the thirdgear cluster rotates with the layshaft;

a fourth gear cluster having one or more gears coupled to a sleevecoaxially mounted over the spindle such that the sleeve rotatesindependently of the spindle;

a continuous second belt or chain coupling the third gear cluster to thesecond gear cluster, such that the third gear cluster drives the fourthgear cluster and the second belt or chain defines a second planeparallel to the first plane;

a chainring fastened to the sleeve, such that the chainring rotates withthe fourth gear cluster; and

a shifting system including a first shifting wedge transitionablebetween:

-   -   (a) a first configuration, in which a first ramped face of the        wedge is in line with the pin of each segment of the inboard        gear of the first gear cluster when the segment is out of the        first plane, such that rotating the pin into the first ramped        face is configured to urge the segment into the first plane, and    -   (b) a second configuration, in which a second ramped face of the        wedge is in line with the pin of each segment of the inboard        gear of the first gear cluster when the segment is in the first        plane such that rotating the pins into the second ramped face is        configured to urge the segment out of the first plane.

A1. The gearbox of A0, wherein the first gear cluster, second gearcluster, first belt or chain, third gear cluster, fourth gear cluster,and second belt or chain are enclosed in a housing.

A2. The gearbox of A0 or A1, wherein an outboard gear of the first gearcluster is nested within the inboard gear, such that the outboard gearis in line with the first plane.

A3. The gearbox of A2, wherein the outboard gear is a non-segmentedgear.

A4. The gearbox of A0 or A1, wherein an outboard gear of the first gearcluster includes a plurality of pivotable outboard segments arranged inpairs with the inboard segments, each pair of outboard and inboardsegments being mounted to a common hinge, such that pivoting the inboardsegment of the pair out of the first plane automatically pivots theoutboard segment of the pair into the first plane.

A5. The gearbox of any one of paragraphs A0 through A4, wherein thedrive spindle is coupled to a crankset configured to rotate the spindle.

A6. The gearbox of any one of paragraphs A0 through A5, wherein thedrive spindle is coupled to an electric motor configured to rotate thespindle.

A7. The gearbox of any one of paragraphs A0 through A6, wherein aninboard gear of the second gear cluster includes a plurality ofpivotable segments, each of which has a respective pin protrudingtransversely from an inboard face.

A8. The gearbox of A7, the shifting system further comprising a secondshifting wedge configured to pivot the segments of the inboard gear ofthe second gear cluster.

A9. The gearbox of any one of paragraphs A0 through A8, wherein arespective inboard gear of each of the third and fourth gear clustersincludes a plurality of pivotable segments, each of which has arespective pin protruding transversely from an inboard face.

B0. A gearbox for a vehicle, the gearbox comprising:

a drive spindle;

a first gear cluster coaxially fastened to the spindle such that thefirst gear cluster rotates with the spindle, the first gear clusterincluding an outboard gear and an inboard gear, wherein the inboard gearis physically divided into a plurality of segments;

a second gear cluster having one or more gears coaxially fastened to alayshaft spaced from and parallel to the spindle, such that the layshaftrotates with the second gear cluster;

a continuous first belt or chain coupling the first gear cluster to thesecond gear cluster, such that the first gear cluster drives the secondgear cluster and the first belt or chain defines a first plane, whereinthe segments of the inboard gear of the first gear cluster are eachmovable into and out of the first plane;

a third gear cluster having one or more gears coaxially fastened to thelayshaft and spaced from the second gear cluster, such that the thirdgear cluster rotates with the layshaft;

a fourth gear cluster having one or more gears coupled to a sleevecoaxially mounted over the spindle such that the sleeve rotatesindependently of the spindle;

a continuous second belt or chain coupling the third gear cluster to thesecond gear cluster, such that the third gear cluster drives the fourthgear cluster;

a chainring fastened to the sleeve, such that the chainring rotates withthe fourth gear cluster; and

a shifting system including an actuator configured to urge the segmentsof the inboard gear of the first gear cluster into and out of the firstplane, such that a gear ratio of the gearbox is changeable withoutdisplacing the first belt or chain out of the first plane.

B1. The gearbox of B0, wherein the segments of the inboard gear of thefirst gear cluster are configured to translate into and out of the firstplane along the spindle.

B2. The gearbox of B0, wherein the segments of the inboard gear of thefirst gear cluster are configured to pivot into and out of the firstplane.

B3. The gearbox of B2, wherein the outboard gear of the first gearcluster includes a plurality of pivotable outboard segments arranged inpairs with the inboard segments, each pair of outboard and inboardsegments being mounted to a common hinge, such that pivoting the inboardsegment of the pair out of the first plane automatically pivots theoutboard segment of the pair into the first plane.

B4. The gearbox of B2, wherein each of the segments of the inboard gearhas a respective pin protruding transversely from an inboard face; and

the actuator of the shifting system includes a shifting wedgetransitionable between:

-   -   (a) a first configuration, in which a first ramped face of the        wedge is in line with the pin of each segment of the inboard        gear of the first gear cluster when the segment is out of the        first plane, such that rotating the pin into the first ramped        face is configured to urge the segment into the first plane, and    -   (b) a second configuration, in which a second ramped face of the        wedge is in line with the pin of each segment of the inboard        gear of the first gear cluster when the segment is in the first        plane such that rotating the pins into the second ramped face is        configured to urge the segment out of the first plane.

B5. The gearbox of B2, wherein a respective inboard gear of each of thesecond, third, and/or fourth gear clusters includes a plurality ofpivotable segments.

B6. The gearbox of B5, the actuator of the shifting system furthercomprising a second shifting wedge configured to pivot the segments ofthe inboard gear of the second gear cluster.

B7. The gearbox of any one of paragraphs B0 through B6, wherein thefirst gear cluster, second gear cluster, first belt or chain, third gearcluster, fourth gear cluster, and second belt or chain are enclosed in ahousing.

B8. The gearbox of any one of paragraphs B0 through B2, wherein anoutboard gear of the first gear cluster is nestable with the inboardgear.

B9. The gearbox of B8, wherein the outboard gear is a non-segmentedgear.

C0. A gearbox for a vehicle, the gearbox comprising:

a drive spindle;

a layshaft spaced from and parallel to the spindle;

a first gear cluster coaxially fastened to one of the spindle or thelayshaft and rotatable therewith, the first gear cluster including anoutboard gear and an inboard gear, wherein the inboard gear isphysically divided into a plurality of segments;

a second gear cluster coaxially fastened to the other of the spindle orthe layshaft and rotatable therewith, the second gear cluster having oneor more gears;

a continuous belt or chain coupling the first gear cluster to the secondgear cluster, such that the belt or chain defines a plane, wherein thesegments of the inboard gear of the first gear cluster are each movableinto and out of the first plane;

a chainring coupled to the layshaft, such that the chainring rotateswith the layshaft; and

a shifting system including an actuator configured to urge the segmentsof the inboard gear of the first gear cluster into and out of the planeof the belt or chain, such that a gear ratio of the gearbox ischangeable without displacing the belt or chain out of the plane.

C1. The gearbox of C0, wherein the segments of the inboard gear of thefirst gear cluster are configured to translate axially into and out ofthe plane of the belt or chain.

C2. The gearbox of C0, wherein the segments of the inboard gear of thefirst gear cluster are configured to pivot into and out of the plane ofthe belt or chain.

C3. The gearbox of C2, wherein the outboard gear of the first gearcluster includes a plurality of pivotable outboard segments arranged inpairs with the inboard segments, each pair of outboard and inboardsegments being mounted to a common hinge, such that pivoting the inboardsegment of the pair out of the plane automatically pivots the outboardsegment of the pair into the plane.

C4. The gearbox of C2, wherein each of the segments of the inboard gearhas a respective pin protruding transversely from an inboard face; and

wherein the actuator of the shifting system includes a shifting wedgetransitionable between:

-   -   (a) a first configuration, in which a first ramped face of the        wedge is in line with the pin of each segment of the inboard        gear of the first gear cluster when the segment is out of the        plane, such that rotating the pin into the first ramped face is        configured to urge the segment into the plane, and    -   (b) a second configuration, in which a second ramped face of the        wedge is in line with the pin of each segment of the inboard        gear of the first gear cluster when the segment is in the plane        such that rotating the pins into the second ramped face is        configured to urge the segment out of the plane.

C5. The gearbox of C2, wherein a respective inboard gear of the secondgear cluster includes a plurality of pivotable segments.

C6. The gearbox of C5, the actuator of the shifting system furthercomprising a second shifting wedge configured to pivot the segments ofthe inboard gear of the second gear cluster.

C7. The gearbox of any one of paragraphs C0 through C6, wherein thefirst gear cluster, second gear cluster, and belt or chain are enclosedin a housing.

C8. The gearbox of any one of paragraphs C0 through C2, wherein anoutboard gear of the first gear cluster is nestable with the inboardgear.

C9. The gearbox of C8, wherein the outboard gear is a non-segmentedgear.

D0. A vehicle drivetrain comprising:

a rotatable gear coupled to a continuous chain or belt defining a plane,the gear divided into a plurality of pivotable segments, such that anouter edge of each of the pivotable segments is transitionable into andout of the plane;

a plurality of segment actuators, each of the segment actuatorsrotatable with and coupled to a respective one of the pivotablesegments;

a linear actuator coupled to a toggle, wherein the linear actuator isconfigured to transition the toggle between:

-   -   (a) a first position, in which a first ramped face of the toggle        is disposed in a path of the segment actuator of each segment        when the segment is out of the plane of the chain or belt, such        that rotating the segment actuator into the first ramped face        urges the segment into the plane, and    -   (b) a second position, in which a second ramped face of the        toggle is disposed in the path of the segment actuator when the        segment is in the plane of the chain or belt, such that rotating        the segment actuator into the second ramped face urges the        segment out of the plane.

D1. The drivetrain of D0, wherein the linear actuator does not rotatewith respect to the rotatable gear.

D2. The drivetrain of paragraph D0 or D1, each of the segment actuatorscomprising a slider coupled to the respective segment by a hinge, eachslider having two spaced-apart protrusions, wherein the toggle isconfigured to selectively interact with the protrusions to translate theslider and pivot the segment.

D3. The drivetrain of D2, wherein the slider is disposed in a guidingplate configured to rotate with the rotatable gear.

D4. The drivetrain of D2 or D3, wherein each hinge includes a pintransversely movable within a slot.

D5. The drivetrain of any one of paragraphs D0 through D4, wherein thetoggle is coupled to the linear actuator by a lever arm, such thatlinear motion of the linear actuator is translated into pivoting motionof the toggle.

D6. The drivetrain of any one of paragraphs D0 through D5, wherein thelinear actuator is controlled by an electronic controller.

E0. A method for shifting a segmented gear, the method comprising:

rotating a gear cluster comprising a first gear and a coaxial secondgear using a power transfer mechanism (e.g., a belt or a chain), whereinthe power transfer mechanism defines a plane and is wrapped partiallyaround the first gear, and wherein the first gear has a plurality ofgear segments independently movable (e.g., pivotable or translatable)into and out of the plane;

rotating a plurality of radially transitionable sliders in tandem withthe first gear, each of the sliders having one or more protrusions andcoupled to a corresponding one of the gear segments of the first gear;

pivoting a toggle into a first position such that a first ramped face ofthe toggle is in a path of the one or more protrusions of the sliders;

sequentially moving each segment of the first gear out of the plane ofthe power transfer mechanism by urging the slider radially when the oneor more protrusions strike the first ramped face of the toggle, suchthat the power transfer mechanism wraps at least partially around thesecond gear.

E1. The method of E0, wherein each of the sliders is coupled to thecorresponding one of the segments by a slotted hinge.

E2. The method of E1, wherein the slotted hinge is on an opposite sideof the slider with respect to the one or more protrusions.

E3. The method of any one of paragraphs E0 through E2, whereinsequentially moving each segment comprises pivoting each segment (e.g.on a pivot axis) transversely (for example, orthogonally) with respectto the plane of the power transfer mechanism.

E4. The method of any one of paragraphs E0 through E3, wherein thesecond gear is unsegmented.

E5. The method of any one of paragraphs E0 through E3, wherein thesecond gear is segmented and each segment of the second gear has a fixedrelationship with each corresponding segment of the first gear, suchthat pivoting one segment of the first gear automatically pivots thecorresponding segment of the second gear.

E6. The method of any one of paragraphs E0 through E5, whereinsequentially moving each segment is performed at a position where eachsegment is unloaded, i.e. substantially free of the power transfermechanism.

E7. The method of any one of paragraphs E0 through E6, wherein thesecond gear is concentric with the first gear.

E8. The method of any one of paragraphs E0 through E7, wherein thesecond gear is nested within the first gear.

E9. The method of any one of paragraphs E0 through E8, wherein teeth ofthe second gear are coplanar with teeth of the first gear.

E10. The method of any one of paragraphs E0 through E9, furthercomprising: pivoting a toggle into a second position such that a secondramped face of the toggle is in a path of the one or more protrusions ofthe sliders;

sequentially moving each segment of the first gear into the plane of thepower transfer mechanism by urging the slider radially within the guideplate when the one or more protrusions strike the second ramped face ofthe toggle, such that the power transfer mechanism wraps at leastpartially around the first gear.

E11. The method of any one of paragraphs E0 through E10, wherein thesliders are disposed in a common guide plate disposed adjacent the firstgear.

Advantages, Features, and Benefits

The different embodiments and examples of the gearbox systems describedherein provide several advantages over known solutions for shifting gearratios of a bicycle. For example, illustrative embodiments and examplesdescribed herein allow a lower weight and greater flexibility in gearingchoices relative to known systems.

Additionally, and among other benefits, illustrative embodiments andexamples described herein allow for at least as many gear ratios as inknown systems (e.g., 12 speeds) in a smaller package.

Additionally, and among other benefits, illustrative embodiments andexamples described herein allow for a gear box that is simpler thanknown systems and/or easier to work on.

Additionally, and among other benefits, illustrative embodiments andexamples described herein are able to function without the need for anysensors relating to rotational position of the gear and/or pivotingposition of the gear segment(s). For example, shifting system 510 isconfigured to function properly independent of any information regardingrotational and/or pivoting positions of the segmented gear.

Additionally, and among other benefits, illustrative embodiments andexamples described herein allow for selectively installing gear clustershaving different numbers of gears in a gear box. Accordingly, gearclusters having more gears or fewer gears may be installed as desired.For example, gear clusters having fewer gears could be used when alighter weight is desired, and gear clusters having more gears could beused when a greater number of gear ratios is desired.

No known system or device can perform these functions. However, not allembodiments and examples described herein provide the same advantages orthe same degree of advantage.

CONCLUSION

The disclosure set forth above may encompass multiple distinct exampleswith independent utility. Although each of these has been disclosed inits preferred form(s), the specific embodiments thereof as disclosed andillustrated herein are not to be considered in a limiting sense, becausenumerous variations are possible. To the extent that section headingsare used within this disclosure, such headings are for organizationalpurposes only. The subject matter of the disclosure includes all noveland nonobvious combinations and subcombinations of the various elements,features, functions, and/or properties disclosed herein. The followingclaims particularly point out certain combinations and subcombinationsregarded as novel and nonobvious. Other combinations and subcombinationsof features, functions, elements, and/or properties may be claimed inapplications claiming priority from this or a related application. Suchclaims, whether broader, narrower, equal, or different in scope to theoriginal claims, also are regarded as included within the subject matterof the present disclosure.

The invention claimed is:
 1. A method for shifting a segmented gear, the method comprising: rotating a gear cluster comprising a first gear and a coaxial second gear, wherein the gear cluster is operatively coupled to a power transfer mechanism, wherein a power transfer mechanism defines a plane and is wrapped partially around the first gear, and wherein the first gear has a plurality of gear segments independently movable into and out of the plane; rotating a plurality of radially transitionable sliders in tandem with the first gear, each of the sliders having one or more protrusions and coupled to a corresponding one of the gear segments of the first gear; pivoting a toggle into a first position such that a first ramped face of the toggle is in a path of the one or more protrusions of the sliders; and sequentially moving each segment of the first gear out of the plane of the power transfer mechanism by urging the slider radially when the one or more protrusions strike the first ramped face of the toggle, such that the power transfer mechanism wraps at least partially around the second gear.
 2. The method of claim 1, wherein each of the sliders is coupled to the corresponding one of the segments by a slotted hinge.
 3. The method of claim 2, wherein the slotted hinge is on an opposite side of the slider with respect to the one or more protrusions.
 4. The method of claim 1, wherein sequentially moving each segment comprises pivoting each segment transversely with respect to the plane of the power transfer mechanism.
 5. The method of claim 1, wherein the second gear is segmented and each segment of the second gear has a fixed relationship with each corresponding segment of the first gear, such that pivoting one segment of the first gear automatically pivots the corresponding segment of the second gear.
 6. The method of claim 1, wherein sequentially moving each segment is performed at a position where each segment is unloaded with respect to the power transfer mechanism.
 7. The method of claim 1, wherein the second gear is nested within the first gear.
 8. The method of claim 7, wherein teeth of the second gear are coplanar with plane of the power transfer mechanism.
 9. The method of claim 7, wherein the second gear is unsegmented.
 10. The method of claim 1, wherein the sliders are disposed in a common guide plate disposed adjacent the first gear.
 11. The method of claim 10, further comprising: pivoting the toggle into a second position such that a second ramped face of the toggle is in a path of the one or more protrusions of the sliders; and sequentially moving each segment of the first gear into the plane of the power transfer mechanism by urging the slider radially within the guide plate when the one or more protrusions strike the second ramped face of the toggle, such that the power transfer mechanism wraps at least partially around the first gear.
 12. A method for shifting a segmented gear, the method comprising: rotating a gear cluster comprising a first gear and a coaxial second gear using a power transfer mechanism, wherein the power transfer mechanism defines a plane and is wrapped partially around the first gear, and wherein the first gear has a plurality of gear segments independently pivotable into and out of the plane; rotating a plurality of radially transitionable sliders in tandem with the first gear, each of the sliders having one or more protrusions and coupled to a corresponding one of the gear segments of the first gear; pivoting a toggle into a first position using a linear actuator, such that a first contoured face of the toggle is in a first path of the one or more protrusions of the sliders; and sequentially moving each segment of the first gear out of the plane of the power transfer mechanism by urging the slider radially when the one or more protrusions strike the first contoured face of the toggle, such that the power transfer mechanism wraps at least partially around the second gear.
 13. The method of claim 12, wherein each of the sliders is coupled to the corresponding one of the segments by a slotted hinge.
 14. The method of claim 1, wherein sequentially moving each segment comprises pivoting each segment on a pivot axis transversely with respect to the plane of the power transfer mechanism.
 15. The method of claim 12, wherein the second gear is segmented and each segment of the second gear has a fixed relationship with each corresponding segment of the first gear, such that pivoting one segment of the first gear automatically pivots the corresponding segment of the second gear.
 16. The method of claim 12, wherein sequentially moving each segment is performed at a position where each segment is free of the power transfer mechanism.
 17. The method of claim 12, wherein the second gear is nested within the first gear.
 18. The method of claim 12, wherein the power transfer mechanism comprises a chain.
 19. The method of claim 12, wherein the sliders are disposed in a common guide plate disposed adjacent the first gear, and the method further comprises: pivoting the toggle into a second position such that a second contoured face of the toggle is in a second path of the one or more protrusions of the sliders; and sequentially moving each segment of the first gear into the plane of the power transfer mechanism by urging the slider radially within the guide plate when the one or more protrusions strike the second contoured face of the toggle, such that the power transfer mechanism wraps at least partially around the first gear.
 20. The method of claim 12, wherein rotating the gear cluster using the power transfer mechanism comprises driving the power transfer mechanism using a second gear cluster. 